Air Delivery System Research Articles

Metabolic engineering of indene bioconversion in Rhodococcus sp.

We have applied the methodology of metabolic engineering in the investigation of the enzymatic bioreaction network in Rhodococcus sp. that catalyzes the bioconversion of indene to (2R)-indandiol suitable for the synthesis of cis-1-amino-2-indanol, a precursor of the HIV protease inhibitor, Crixivan. A chemostat with a novel indene air delivery system was developed to facilitate the study of steady state physiology of Rhodococcus sp. 124. Prolonged cultivation of this organism in a continuous flow system led to the evolution of a mutant strain, designated KY1, with improved bioconversion properties, in particular a twofold increase in yield of (2R)-indandiol relative to 124. Induction studies with both strains indicated that KY1 lacked a toluene-inducible dioxygenase activity present in 124 and responsible for the formation of undesired byproducts. Flux analysis of indene bioconversion in KY1 performed using steady state metabolite balancing and labeling with [14C]-tracers revealed that at least 94% of the indene is oxidized by a monooxygenase to indan oxide that is subsequently hydrolyzed to trans-(1R,2R)-indandiol and cis-(1S,2R)-indandiol. This analysis identified several targets in KY1 for increasing (2R)-indandiol product yield. Most promising among them is the selective hydrolysis of indan oxide to trans-(1R,2R)-indandiol through expression of an epoxide hydrolase or modification of culture conditions.

Localised air delivery systems in the food industry

The transfer of contamination through the airborne route is significant in the assembly area of high-care food factories preparing products such as sandwiches, prepared salads and chilled meals. This paper describes equipment designs that have been proposed to restrict such contamination and maintain low air temperatures around the food whilst allowing higher factory temperatures. Designs based on uni-directional flows, open troughs, semi-closed and closed tunnels are described. The uni-directional flow systems have been applied successfully in the chilled food industry although they require higher air flows than the other systems. Troughs offer good maintenance of temperature and low airborne counts around the food. Tunnels are more expensive and there are concerns about clean-ability of the equipment and, with the closed tunnels based on glove-box technology, potential problems of operator comfort.

DESIGN, CONSTRUCTION, AND EVALUATION OF A COMPACT RECIRCULATINGWIND TUNNEL FOR AGRICULTURAL EXPERIMENTS

The purpose of this study was to design, construct, and evaluate the performance of a compact, low-speed wind tunnel. The wind tunnel was designed particularly for small scale agricultural experiments in a controlled environment. The design criteria for air velocity, temperature, and relative humidity were 0 m/s~10 m/s, 0°C~50°C, and 10%~95%, respectively. The overall length was limited to about 3.5 m. An air delivery system, a heat exchanger, and a humidifier unit were installed and tested. The study successfully demonstrated the feasibility of simulating velocity, humidity, and temperature controlled environments in a limited space. A spatially uniform and steady free stream was achieved in at least 64% of the transverse cross-section of the test section. The system was able to maintain desired conditions for an extended period of time.

Evaluation of Foliar Insecticide Efficacy Against Thrips in Cotton, 1996

Abstract Cotton seed was planted in a Gigger silt loam on 1 May at the Macon Ridge location of the Northeast Research Station. The seed was treated with Orthene 80S (8 oz form/cwt seed) and Terraclor Super X (10 lb form./acre) was applied at planting to reduce seeding disease problems. Plots in this test consisted of 2 rows (40 inch centers) X35 ft. Treatments were arranged in a RCB with 4 replications. Insecticides were applied with a tractor mounted boom equipped with a compressed air delivery system calibrated to deliver 10 gal total spray/acre through Teejet 80015 flat fan nozzles (2/row) at 20 psi. Plots were treated on 15 May and sampled on 17 (2 DAT), 20 (5 DAT), and 23 May (8 DAT). Treatments were evaluated by randomly collecting 10 plants in each plot and processing samples with whole plant washing procedures. Data were analyzed with ANOVA, and means were separated according to DMRT. No rainfall occurred during this test.

The Effect of Adjuvants on Foliar Insecticide Efficacy Against Thrips in Cotton, 1995

Abstract Cotton seed was planted in a Gigger silt loam on 11 May at the Macon Ridge location of the Northeast Research Station. The seed was treated with Orthene 80S (8 oz form/cwt seed) and Terraclor Super X (10 lb form/acre) was applied at planting to reduce seedling disease problems. Plots in this test consisted of 2 rows (40 inch centers) X 25 ft. Treatments were arranged in a RCB with 4 replications. Insecticides were applied with a tractor mounted boom equipped with compressed air delivery system calibrated to deliver 10 gpa through Teejet TVS 8001 flat fan nozzles (2/row) at 38 psi. Plots were treated on 25 May and sampled on 28 May (3 DAT), 30 May (5 DAT) and 1 Jun (7 DAT). Treatments were evaluated by randomly collecting 10 plants in each plot and processing samples with whole plant washing procedures. These plots received 0.23 inches of rainfall on 31 May and 0.58 inch of rainfall on 1 Jun. Data were analyzed with ANOVA, and means were separated according to DMRT.

Evaluation of Scout X-Tra and Decis Formulations Against Bollworm and Tobacco Budworm, 1994

Abstract Cotton was planted 2 Jun into plots consisting of 4 rows (40 inch centers) × 50 ft. Treatments were arranged in an RCB design with 4 replications. Applications were made with a high clearance sprayer and compressed air delivery system calibrated to deliver 6 gal total spray/acre through Teejet X- 8 hollow cone nozzles (2/row) at 46 psi. Insecticide treatments were applied on 12, 15, 22 Aug. Methyl parathion 4 EC (0.33 lb (AI)/acre) was applied on an “as needed” basis for boll weevil control. Treatment efficacy was determined by examining 50 squares for evidence of damage. The center two rows of each plot were mechanically harvested on 12 Oct to estimate seedcotton yields. The test area received 0.11, 1.9 and 0.13 inches rainfall on 13, 20, 21 Aug, respectively. Supplemental irrigation was provided by an overhead system sprinkler “as needed” during the season, but not within 48 h of treatment applications.

Persistence of Dipel Es, 1994

Abstract Dipel ES was evaluated for persistence and efficacy against tobacco budworm in a field of Deltapine 51 cotton planted at the Macon Ridge Branch of the Northeast Research Station near Winnsboro, LA on 18 Apr. Plots consisted of two rows of cotton plants (40 inch centers) by 50 ft. Treatments were arranged in a RCB design with 4 replications. Insecticide treatments (untreated, Dipel ES at 4.0 and 16 oz (form)/acre) were evaluated at 3 time intervals after treatment (2, 24 and 48 h). Insecticides were applied on 6 Jun with a tractor mounted spray boom equipped with a compressed air delivery system calibrated to deliver 10 GPA at 42 psi through two 8001 fiat fan nozzles equally spaced per row. No rainfall occurred during this study. At 2, 24 and 48 h after insecticide application (HAT), 25 cotton plant terminals were randomly collected from each plot and placed in florist water pics. Two 2nd instar LSU-LAB tobacco budworm larvae (S4 days old; 3.3-7.7 mg) were placed on each plant terminal. Larvae were confined to plant terminals for 72 h after which mortality was recorded. A larva was considered dead if it was unable to right itself within 15 s after being prodded. Mortality was corrected for that observed on untreated plant terminals using Abbott’s formula. All data were subjected to ANOVA and means were compared using Least Significant Differences.

The Effect of Adjuvants on Foliar Insecticide Efficacy Against Thrips in Cotton, 1994

Abstract Cotton was planted in a Gigger silt loam on 18 Apr. Plots consisted of 2 rows on (40 inch centers) × 40 ft. The seed was treated with Orthene 80S (8 oz form/cwt seed) and Terraclor Super × (10 lb form/acre) was applied at planting to reduce seedling disease problems. Treatments were arranged in a RCB with 4 replications. Insecticides were applied with a tractor mounted boom equipped with compressed air delivery system calibrated to deliver 10 gal total spray/acre through Teejet TVS 8001 flat fan nozzles (2/row) at 48 psi. Plots were treated on 18 May and sampled on 20 May (2 DAT), 23 May (5 DAT) and 25 May (7 DAT). Treatments were evaluated by randomly collecting 10 plants in each plot and processing samples with whole plant washing procedures. No rainfall was recorded during this test.

Laboratory Bioassay of Selected Bt Insecticides Against Tobacco Budworm, 1994

Abstract Selected Bt insecticides were evaluated for efficacy and persistence against a laboratory colony of tobacco budworm (STV-LAB, USDA-ARS Southern Insect Management Laboratory, Stoneville, MS). Treatments were arranged in a RCB design with 5 replications. Deltapine 51 cotton was planted 3 Jun in plots of 4 rows (40 inch centers) by 50 ft. Treatments were applied on 29 Jul with a tractor mounted spray boom equipped with a compressed air delivery system calibrated to deliver 10 GPA at 29 psi through two 8002 flat fan nozzles equally spaced per row. At 2 and 72 h after insecticide application, 10 cotton plant terminals were randomly collected from the center rows within each plot and placed in 1 oz clear plastic cups. One 2nd instar larva (≥3 days old; 3.3-7.7 mg) was placed in each cup and confined to plant terminals for 72 h. A larva was considered dead if it was unable to right itself within 15 s after being prodded.

Acute Ulcers Induced in Canine Stomachs by Endoscopic Compressed Air Delivery of 25 mg NaCl

Abstract: Endoscopic administration of 25 mg NaCl powder to target sites on the gastric mucosa of five dogs, using a compressed air delivery system developed by the author, was followed by observation of changes in the gastric mucosa. After 30 seconds, 1 minute, 2 minutes, 5 minutes and 10 minutes, the sprayed NaCl was washed away by endoscopic water spray, and the presence of submucosal bleeding was observed at the target sites. After 24 hours, ulcers in the gastric mucosa were recognized at sites at which the NaCl had been in contact for 2 minutes or more before being washed away. With one minute or less contact time between NaCl and the mucosa, erosion and redness were observed at the target sites. In a control study, however, no mucosal lesions occurred following identical spray of 25 mg lactose powder which was left in contact for 30 seconds, 1 minute, 2 minutes, 5 minutes and 10 minutes, and also 24 hours.Experimental gastric ulcers can be induced by endoscopic administration of a small amount of NaCl powder. The time of contact of NaCl on the gastric mucosa affected the induction of gastric mucosal damage. This method will be useful in the investigation of the direct effects of various drugs on the gastric mucosa.

Efficacy of Insecticide Mixtures Against Bollworm and Tobacco Budworm During Late Season, 1993

Abstract Cotton was planted in a Gigger-Gilbert silt loam on 1 Jul. Plots consisted of 3 rows on 1.02 m centers × 12.2 m. Treatments were arranged in a RCBD with 4 replications. Field preparation and plot maintenance followed conventional cultural practices. Plots were irrigated to maintain satisfactory soil moisture. All treatments were applied with a tractor mounted boom equipped with a compressed air delivery system calibrated to deliver 93.5 liters total spray/ha through TX-8 hollow cone nozzles (2/row) at 2.3 kg/cm2. Treatments were applied on 7 and 10 Sep and evaluated on 14 Sep (4 DAT) by visually examining 50 squares on each of 2 rows/plot for boll worm-tobacco budworm damage and live larvae. All plots were heavily infested with eggs and larvae (primarily tobacco budworm) on 7 Sep. No other insecticides were applied to the test area. The plots received 1.7 cm rainfall on 13 Sep (3 DAT).

Effects of Butacide on Control of Bollworm and Tobacco Budworm with Ammo, 1993

Abstract Butacide 8 EC was evaluated for its effect on the control of BW and TBW in combination with Ammo 2.5 EC at the Macon Ridge Branch of the Northeast Research Station near Winnsboro, LA in irrigated cotton planted 1 Jul. The test consisted of a RBD with 4 replications of 3 row (1.02 m centers) × 9.1 m plots. The test was treated on 2, 6 and 10 Sep. All treatments were applied with a tractor mounted boom and compressed air delivery system. Treatments in the test were applied with the spray boom calibrated to deliver 56.1 liters/ha at 2.1 kg/cm2 through 2, TX-8 nozzles equally spaced per row. The test was evaluated on 6, 10 and 16 Sep. Treatments were evaluated by visually examining 50 randomly picked squares per plot for damage and live BW and TBW larvae. The plots received 0.4 cm rainfall on 12 Sep and 1.3 cm rainfall on 13 Sep.

Technique for Measuring Air Flow and Carbon Dioxide Flux in Large, Open‐Top Chambers

AbstractOpen‐Top Chambers (OTCs) are commonly used to evaluate the effect of CO2, O3, and other trace gases on vegetation. A study was conducted to develop and test a new technique for measuring forced air flow and net CO2 flux from OTCs. Experiments were performed with a 4.5‐m diam. OTC that had a sealed floor and a specialized air delivery system. Air flow through the chamber was computed with the Bernoulli equation using measurements of the pressure differential between the air delivery ducts and the chamber interior. An independent measurement of air flow was made simultaneously to calibrate and verify the accuracy of the Bernoulli relationship. The CO2 flux density was calculated as the product of chamber air flow and the difference in CO2 concentration between the air entering and exhausting from the OTC (Cin ‐ Cout). Accuracy of the system was evaluated by releasing CO2 within the OTC at known rates to emulate respiration from the field surface. Data were collected with OTCs at ambient and elevated CO2 (≈700 µmol mol−1). Results showed that the Bernoulli equation, with a flow coefficient of 0.7, accurately measured air flow in the OTC to within ±5% regardless of flow rate and air duct geometry. Experiments in ambient OTCs showed that CO2 flux density (µmol m−2 s−1), computed from 2‐min averages of air flow and Cin ‐ Cout, was typically within ±10% of actual flux, provided that the exit air velocity at the top of the OTC was greater than 0.6 m s−1. Obtaining the same level of accuracy in CO2‐enriched OTCs, however, required a critical exit velocity near 1.2 m s−1 to minimize the incursion of ambient air and prevent contamination of the exit gas sample. When flux data were integrated over time to estimate daily CO2 flux (µmol m−2 d−1), actual and measured values agreed to within ±2% for both ambient and CO2‐enriched chambers, suggesting that accurate measurements of daily net C exchange are possible with this technique.

Evaluation of Insecticide Mixtures Against Bollworm and Tobacco Budworm, 1992

Abstract Cotton was planted 9 Jun into plots consisting of 5 rows (102 cm centers) x 15 m. at the Macon Ridge Branch, NE Research Station at Winnsboro, LA. Treatments were arranged in a RCB design, replicated 4 times. Applications were made with a high clearance sprayer and compressed air delivery system calibrated to deliver 56.2 liters total spray/ha through Teejet X-8 hollow cone nozzles (2/row) at 2.11 kg/cm2. Insecticide treatments were applied on 7, 12, 17, 20, and 26 Aug. Methyl parathion 4 EC (0.37 kg [AI]/ha) was applied on an “as needed” basis for boll weevil control. Treatment efficacy was determined by examining 25 squares/plot for evidence of damage. In addition, the number of larval damaged bolls/3.3 m section of row was recorded on 9 Oct. The center 2 rows of each plot were mechanically harvested on 12 Oct to estimate seed cotton yields. The test area received 1.2 cm rainfall on 9 Aug, 0.6 cm rainfall on 11 Aug, a trace of rainfall on 12 and 24 Aug, 11.5 cm rainfall on 26 Aug and 1.3 cm rainfall on 27 Aug. Supplemental irrigation was provided by an overhead system sprinkler “as needed” during the season, but not within 48 h of treatment applications.

Eakly Season Insect Control with Foliar Insecticides, 1992

Abstract Cotton was planted in a Gigger silt loam on 1 May. Plots consisted of 4 rows on 101.6 cm centers x 15.2 m. The test field was not treated with an in-furrow insecticide at planting, but Terraclor Super X (11.2 kg form/ha) was applied to control seedling diseases. Treatments were arranged in a RCB design with 4 replications. In Test 1, insecticides were applied with a tractor mounted boom equipped with a compressed air delivery system calibrated to deliver 93.6 liters total spray/ha through Teejet TVS 8002 flat fan nozzles (2/ row) at 2.11 kg/cm2. In Test 1, plots were treated on 29. May and sampled on 1 Jun (3 DAT), 3 Tun (5 DAT), and 5 Jun (7 DAT). In Test 2, insecticides were applied with a hand boom equipped with CO2 delivery system calibrated to deliver 93.6 liters total spray/ha through Teejet 80015 flat fan nozzles (2/row) at 2.11 kg/cm2. In Test 2, plots were treated on 10 Jun and sampled on 12 Jun (2 DAT), 15 Jun (5 DAT), and 17 Jun (7 DAT). Treatments were evaluated by randomly collecting 10 plants each plot and processing samples with whole plant washing procedures. The plots in Test 1 received 1.1 cm rainfall on 1 Jun, 0.5 cm rainfall on 2 Jun, and a trace amount of rainfall on 3 Jun. The plots in Test 2 received 1.4 cm rainfall on 10 Jun, a trace amount of rainfall on 11 Jun, and 4.9 cm of rainfall on 14 Jun.

Soybean Looper Control with Selected Bt Insecticides, 1992:

Abstract The efficacy of selected Bacillus thuringiensis (Bt) insecticides was evaluated for soybean looper control at the Macon Ridge Branch of the Northeast Research Station near Winnsboro, LA. The test consisted of a randomized block design with 4 replications. Plots were 5 rows (1.02 m centers) by 9.0 m of soybeans in the R5 growth stage planted 18 Jun. Treatments were applied with a tractor mounted boom equipped with a compressed air delivery system calibrated to deliver 93.5 liters/ha at 2.8 kg/cm2 through 2, TX-8 hollow cone nozzles equally spaced per row. Insecticides were applied on 1 Sep and treatments were evaluated at 2 and 7 DAT using 2 samples of 20 sweeps with a standard 38.2 cm diam sweep net. The plots received 3.0 cm rainfall on 2 Sep and a trace amount of rainfall on 3 Sep.

Evaluation of Dipel Es for Control of Bollworm and Tobacco Budworm (Bw-Tbw), 1992:

Abstract Dipel ES was evaluated for control of BW-TBW at the Macon Ridge Branch of the Northeast Research Station near Winnsboro, LA in three tests. Test 1 consisted of a randomized block design with 5 replications of ‘DPL 51’ cotton planted 17 May in plots consisting of 3 rows (1.02 m centers) x 15.2 m. Test 2 consisted of a randomized block design with 4 replications of ‘Stv 453’ cotton planted 10 May in plots consisting of 4 rows (1.02 m centers) x 15.2 m. Test 3 consisted of a randomized block design with 4 replications of ‘Stv 453’ cotton planted 10 Jul in plots of 3 rows (1.02 m centers) X 15.2 m. Test 1 was treated on 21 Jul, Test 2 on 29 Jul and Test 3 on 6 Aug. All treatments were applied with a tractor mounted boom and compressed air delivery system. Treatments in Tests 1 and 2 were applied with the spray boom calibrated to deliver 102.8 liters/ha at 2.3 kg/cm2 through 2, TX-8 nozzles equally spaced per row. Treatments were applied to Test 3 with the spray boom calibrated to deliver 93.5 liters/ha at 2.1 kg/cm2 through 2, TX-8 nozzles equally spaced per row. Test 1 was evaluated on 24 Jul, Test 2 on 3 Aug and Test 3 on 10 Aug. Evaluation of treatments consisted of visual examination of 100 randomly picked squares per plot for damaged squares and live BW-TBW larvae. In Test 1, the plots received 0.43 and 0.28 cm rainfall on 22 Jul and 23 Jul. In Test 2, no rainfall occurred. In Test 3, the plots received 1.22 cm rainfall on 9 Aug.

Evaluation of Selected Bt Compounds for Bollworm and Tobacco Budworm Control, 1992:

Abstract The efficacy of selected Bacillus thuringiensis (Bt) insecticides was evaluated for bollworm/tobacco budworm (BW-TBW) control at the Macon Ridge location of the Northeast Research Station near Winnsboro, LA. The tests consisted of a RBD with 3 replications repeated on 3 rows (1.01 m centers) by 15.2 m of ‘DPL 51’ cotton planted 8 May. Treatments were applied with a tractor mounted spray boom equipped with a compressed air delivery system calibrated to deliver 93.5 liters/ha at 2.2 kg/cm2 through 2 TX-8 hollow cone nozzles equally spaced per row. Insecticides were applied 21 Jul, 20 Aug and 25 Aug. Treatments were evaluated at 3, 5 and 7 DAT for each test. BW-TBW square damage, etching and feeding evaluations were made after the first test by visually examining 100 squares from each of the 2 center rows of each plot. BW-TBW square damage, etching and feeding evaluations were made after the 2nd and 3rd test by examining 50 squares from each of the 2 center rows of each plot. Etching is a rating based on visible signs of feeding without puncturing the square. Feeding is squares that were damaged plus squares that were etched. For date 1, the plots received 0.4 and 0.3 cm rainfall on 22 and 23 Jul respectively. For date 2, the plots received 0.3 cm rainfall on 23 Aug. For date 3, the plots received 11.4 and 1.27 cm rainfall on 26 and 27 Aug respectively.

Soybean Looper Control with Dipel Es, 1992:

Abstract The efficacy of Dipel ES at selected rates was compared to a recommended rate of Larvin and an untreated control for soybean looper control at the Macon Ridge Branch of the Northeast Research Station near Winnsboro, LA. The test consisted of a randomized block design with 4 replications. Plots were 5 rows (1.02 m centers) by 9.0 m of soybeans in the R5 growth stage planted 18 Jun. Treatments were applied with a tractor mounted boom equipped with a compressed air delivery system calibrated to deliver 93.6 liters/ha at 2.8 kg/cm2 through 2 TX-8 hollow cone nozzles equally spaced per row. Insecticides were applied on 1 Sep and treatments were evaluated at 2 and 7 DAT using 2 samples of 20 sweeps with a standard 38.2 cm diam sweep net. The plots received 3.0 cm rainfall on 2 Sep and a trace amount of rainfall on 3 Sep.

Efficacy of Selected Bacillus Thubingiensis Formulations Against Bollworm and Tobacco Budworm, 1991

Abstract The experimental design was a randomized complete block, with 7 treatments and a control replicated 4 times. Cotton was planted on 16 May with plots consisting of 5 rows (on 102 cm centers) X 13.7 m. Treatments were applied as foliar sprays (pH of water was 7.0) with a hi-clearance tractor equipped with a compressed air delivery system. Two TX-8 hollow cone nozzles equally spaced per row delivered a total vol of 56.2 liters/ha at 3.02 kg/cm2. All plots were oversprayed twice with methyl parathion 4 EC at 0.34 kg (AI)/ha for boll weevil suppression. Treatments were applied on 29 Jul and 14 Aug and all plots were mechanically harvested on 2 Oct. On 1 and 8 Aug, 25 terminals/plot were sampled for boUworm and tobacco budworm eggs, larvae and damage. On these dates, 25 squares/plot were examined for worm damage. Live larvae/25 squares were counted on 1, 7, and 19 Aug. On 19 Aug, 25 bolls/plot were examined for larval damage. Rainfall was recorded on 9 Aug (0.41 cm) and 10 Aug (2.06 cm).