Possible future increases in atmospheric temperature may threaten wheat (Triticum aestivum L.) production and food security. The purpose of this research is to determine the response of wheat growth ...to supplemental heating and to seasonal air temperature from an unusually wide range of planting dates. A field study was conducted at Maricopa, AZ, where wheat was planted from September to May over a 2-yr period for a total of 12 planting dates. Supplemental heating was provided for 6 of the 12 planting dates using infrared heaters placed above the crop which increased canopy temperature by 1.3°C during the day and 2.7°C during the night. Grain yield declined 42 g m−2 (6.9%) per 1°C increase in seasonal temperature above 16.3°C. Supplemental heating had no effect on grain yield for plantings in winter (Dec./Jan.) since temperatures were near optimum (14.9°C). However, in spring (Mar.) plantings where temperature (22.2°C) was above optimum, supplemental heating decreased grain yield from 510 to 368 g m−2. Supplemental heating had the greatest effect in the early fall plantings (Sept./Oct.) when temperature was slightly below optimum (13.8°C) and mid-season frost limited the yield of unheated plots to only 3 g m−2 whereas yield of heated plots was 435 g m−2. Thus, possible future increases in temperature may decrease wheat yield for late plantings and shift optimum planting windows to earlier dates in areas of the world similar to the desert southwest of the United States.
The use of bacteria as an alternative cancer therapy has been reinvestigated in recent years. SL7207: an auxotrophic Salmonella enterica serovar Typhimurium aroA mutant with immune‐stimulatory ...potential has proven a promising strain for this purpose. Here, we show that systemic administration of SL7207 induces melanoma tumor growth arrest in vivo, with greater survival of the SL7207‐treated group compared to control PBS‐treated mice. Administration of SL7207 is accompanied by a change in the immune phenotype of the tumor‐infiltrating cells toward pro‐inflammatory, with expression of the TH1 cytokines IFN‐γ, TNF‐α, and IL‐12 significantly increased. Interestingly, Ly6C+MHCII+ monocytes were recruited to the tumors following SL7207 treatment and were pro‐inflammatory. Accordingly, the abrogation of these infiltrating monocytes using clodronate liposomes prevented SL7207‐induced tumor growth inhibition. These data demonstrate a previously unappreciated role for infiltrating inflammatory monocytes underlying bacterial‐mediated tumor growth inhibition. This information highlights a possible novel role for monocytes in controlling tumor growth, contributing to our understanding of the immune responses required for successful immunotherapy of cancer.
Salmonella Typhimurium can target tumors and stall their growth in mouse models, a process associated with tumor infiltration by inflammatory monocytes. Clodronate liposomes, which abrogate phagocytic cells, inhibit Salmonella‐mediated tumor growth inhibition, suggesting a role for these cells in Salmonella’s antitumor properties.
A first-in-human phase I trial of Vvax001, an alphavirus-based therapeutic cancer vaccine against human papillomavirus (HPV)-induced cancers was performed assessing immunological activity, safety, ...and tolerability. Vvax001 consists of replication-incompetent Semliki Forest virus replicon particles encoding HPV16-derived antigens E6 and E7. Twelve participants with a history of cervical intraepithelial neoplasia were included. Four cohorts of three participants were treated per dose level, ranging from 5 × 105 to 2.5 × 108 infectious particles per immunization. The participants received three immunizations with a 3-week interval. For immune monitoring, blood was drawn before immunization and 1 week after the second and third immunization. Immunization with Vvax001 was safe and well tolerated, with only mild injection site reactions, and resulted in both CD4+ and CD8+ T cell responses against E6 and E7 antigens. Even the lowest dose of 5 × 105 infectious particles elicited E6/E7-specific interferon (IFN)-γ responses in all three participants in this cohort. Overall, immunization resulted in positive vaccine-induced immune responses in 12 of 12 participants in one or more assays performed. In conclusion, Vvax001 was safe and induced immune responses in all participants. These data strongly support further clinical evaluation of Vvax001 as a therapeutic vaccine in patients with HPV-related malignancies.
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Komdeur, Singh, et al. report on a first-in-human phase I clinical trial of a Semliki Forest virus-based cancer vaccine. The trial shows that the vaccine is safe and well tolerated, inducing strong HPV16 E6- and E7-specific CD8 and CD4 T cell responses.
Crop models must be improved to account for the effects of heat stress events on crop yields. To date, most approaches in crop models use air temperature to define heat stress intensity as the ...cumulative sum of thermal times (TT) above a high temperature threshold during a sensitive period for yield formation. However, observational evidence indicates that crop canopy temperature better explains yield reductions associated with high temperature events than air temperature does. This study presents a canopy level energy balance using Monin–Obukhov Similarity Theory (MOST) with simplifications about the canopy resistance that render it suitable for application in crop models and other models of the plant environment. The model is evaluated for a uniform irrigated wheat canopy in Arizona and rainfed maize in Burkina Faso. No single variable regression relationships for key explanatory variables were found that were consistent across sowing dates to explain the deviation of canopy temperature from air temperature. Finally, thermal times determined with simulated canopy temperatures were able to reproduce thermal times calculated with observed canopy temperature, whereas those determined with air temperatures were not.
•Crop canopy temperature is needed to explain yield losses due to high temperatures.•A canopy level energy balance using Monin–Obukhov Similarity Theory (MOST) is presented.•Simplifications about the canopy resistance render it suitable for application in crop models.•The model is evaluated for a irrigated wheat canopy in Arizona and rainfed maize in Burkina Faso.
Abstract
We investigate the relation between gas and star formation in subgalactic regions, ∼360 pc to ∼1.5 kpc in size, within the nearby starburst dwarf NGC 4449, in order to separate the ...underlying relation from the effects of sampling at varying spatial scales. Dust and gas mass surface densities are derived by combining new observations at 1.1 mm, obtained with the AzTEC instrument on the Large Millimeter Telescope, with archival infrared images in the range 8–500
μ
m from the
Spitzer Space Telescope
and the
Herschel Space Observatory
. We extend the dynamic range of our millimeter (and dust) maps at the faint end, using a correlation between the far-infrared/millimeter colors
F
(70)/
F
(1100) (and
F
(160)/
F
(1100)) and the mid-infrared color
F
(8)/
F
(24) that we establish for the first time for this and other galaxies. Supplementing our data with maps of the extinction-corrected star formation rate (SFR) surface density, we measure both the SFR–molecular gas and the SFR–total gas relations in NGC 4449. We find that the SFR–molecular gas relation is described by a power law with an exponent that decreases from ∼1.5 to ∼1.2 for increasing region size, while the exponent of the SFR–total gas relation remains constant with a value of ∼1.5 independent of region size. We attribute the molecular law behavior to the increasingly better sampling of the molecular cloud mass function at larger region sizes; conversely, the total gas law behavior likely results from the balance between the atomic and molecular gas phases achieved in regions of active star formation. Our results indicate a nonlinear relation between SFR and gas surface density in NGC 4449, similar to what is observed for galaxy samples.
Climate warming may raise wheat (Triticum aestivum L.) yields in cooler climates and lower them in warmer climates. To understand these contrasting effects, infrared heating lamps were used to warm ...irrigated spring wheat by 1.5°C (day) and 3.0°C (night) above unheated controls during different times of the year at Maricopa, AZ. Changes in wheat growth with warming were used to test hypotheses for temperature effects on crop growth in the process model ecosys. Infrared heating substantially raised phytomass growth and grain yield under lower air temperature (Ta) following plantings from September through December. The same heating, however, lowered growth and yield under higher Ta following plantings from January through March. Gains in wheat yield of as much as 200 g C m−2 with heating under lower Ta were attributed in the model to more rapid CO2 fixation and to reduced chilling effects on seed set. These gains were only partially offset by losses from shortened wheat growth periods. Losses in wheat yield of as much as 100 g C m−2 with heating under higher Ta were attributed in the model to adverse effects of heating on crop water status and on CO2 fixation vs. respiration, to greater heat stress effects on seed set, and to shortened crop growth periods. Model hypotheses thus explained contrasting effects of heating on wheat yields under different Ta found in the field experiment as well as in many earlier studies. Well-constrained tests of these hypotheses are vital for models used to project climate change impacts on agricultural ecosystems.
A comprehensive kinetic study of a potential daytime nitrous acid (HONO) source reaction, the photoenhanced reduction reaction of the nitrogen dioxide (NO
2
) on acidic humic acid (HA), was completed ...using a wetted-wall flow tube (WWFT) (Fickert et al.: J. Phys. Chem. A. 102, 10689,
1998
) photoreactor integrated with a high sensitivity HONO analyser (Wall et al.: J. Atmos. Chem. 55, 31–54,
2006
; Huang et al.: Atmos. Environ. 36, 2225–2235,
2002
). The nature of this reaction, is of great interest since recently observed, unpredictably high HONO daytime concentrations demand its ordinarily proposed heterogeneous source to proceed 60 times more rapidly at noon than during the night (Kleffmann et al.: ChemPhysChem 8, 1137–1144,
2007
). This study investigated the nature of the reduction reaction with simulated colloidal HA aqueous solutions characteristic of anaerobic environmental conditions, varying in acidity, concentration and composition. Typical urban NO
2
levels were investigated. Increasing photoenhanced HONO production with weakening solution acidity was detected due to increased deprotonation of the carboxyl groups within the humic acid. It was deduced that the acidic HA substrate contains numerous feasible chromophoric sensitizer units capable of photochemically reducing NO
2
to HONO, owing to its ‘biofilm’ (Donlan, 2002) function under UV exposure. The mechanism was found to be more effective for HA standards with higher levels of ‘bioactivity’ (refractivity). Using a complex mathematical model developed, incorporating both chemistry and diffusion, reaction probability datasets were produced from the experimental data, providing evidence that this is, indeed, an environmentally important daytime HONO surface source reaction. The parameters required to scale up the data of the photoreactor to that of a regional rural/urban scale were assessed.
•Sorghum accumulates dhurrin (cyanide) and nitrate; forage can be toxic.•Partitioning of N to cyanide and nitrate was measured in FACE studies.•Cyanide, nitrate accumulation depended on tissue type, ...plant age and irrigation.•Drought effected increases in cyanide and nitrate were not moderated at high CO2.•Risk of toxicity likely to increase with climate change but not directly from rising CO2.
Sorghum Sorghum bicolor (L.) Moench is the world’s fifth most important crop, grown for forage, grain, and as a biofuel. Fast growing and drought tolerant, it is increasingly being planted as a climate change-ready alternative to maize. All parts of the sorghum plant except the grain contain the cyanogenic glucoside dhurrin, which breaks down to release hydrogen cyanide (prussic acid) when plant tissue is disrupted. Fresh forage, hay and silage may be toxic to stock when derived from plants that are young, droughted or heavily fertilized. Sorghum also stores nitrate, which can cause nitrite toxicity. The impact of elevated CO2 on dhurrin and nitrate concentration is unknown. It is important to understand how global environmental change will affect composition in order to be able to predict the safety of the crop in coming decades. Sorghum was grown experimentally at elevated CO2 in two free-air CO2 enrichment (FACE) experiments at ambient and elevated CO2 (ca. 550ppm) and either irrigated regularly or only once after sowing in consecutive years and sampled at different stages of development. Since FACE-grown sorghum has been shown to have improved water status we hypothesized that they would contain less dhurrin. We found the most important factors governing cyanide concentration were (in decreasing order): plant age, irrigation treatment and tissue type. For nitrate, tissue type was by far the most important factor, followed by plant age, and then irrigation treatment. The concentration of CO2 in the atmosphere had no significant effect on the total nitrogen concentration, or the concentrations of cyanide and nitrate. As sorghum is becomes more widely used for forage, it will be important to have simple methods to assess the cyanide levels in the field or to develop new, low cyanogenic varieties to ensure that it is safe for grazing.
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