Agriculture and plant science.

Chair: Evelin J. Cuadra, Alcorn State University 

Vice-chair: Gregorio B. Begonia, Jackson State University 

FRIDAY MORNING

Hunter Henry Ballroom B

8:15 ENHANCING SUSTAINABLE PRODUCTION OF MEDICINAL PLANTS IN MISSISSIPPI

Patrick Igbokwe*, Liang Huam, Franklin Chukwuma, and Magid Dagher, Alcorn State University, Alcorn State, MS 39096

Field studies were used to determine the effect of 3 cropping systems and 3 row preparations on purple coneflower (Echinacea purpurea) survival, growth, yield and quality. The study was conducted on a Memphis silt loam soil in southwest Mississippi. A split plot arrangement in a randomized complete block experiment design was used for this study. The 3 cropping systems made up the main-plot, whereas the 3 row preparations made up the sub-plot. Each of the 3 row preparations was replicated 4 times. Cropping systems influenced plant survival, canopy height, root dry weight and root volatile soil during both 2004 and 2005 study periods. Row preparations also influenced plant survival, canopy height and root volatile oil during the same period.

8:30 REOCCURRENCE OF ANGULAR LEAF SPOT OF COTTON IN MISSISSIPPI AND EVALUATION OF CURRENTLY GROWN VARIETIES FOR IMMUNITY OR RESISTANCE TO THE DISEASE.

G. L. Sciumbato*, P. S. Thaxton, and Jim Nichols, Delta Research and Extension Center, Mississippi State University, Stoneville, MS 38776

Angular leaf spot or bacterial blight was a major disease of cotton (Gosspyium hursitum) in Mississippi prior to the use of acid delinted cotton. The bacterium is mostly transmitted on the surface of the seed and the acid delinting process eliminated the bacterium. There was also genetic resistance to the disease. However, the major source of resistance was Tamcot SP-37 and varieties with a SP-37 background were very susceptible to bronze wilt and were discontinued. In addition, environmental concerns about acid delinting have resulted in newer methods of removing the lint from cotton which do not use acid. These new methods allow the bacterium to survive the delinting process. The bacterium has been isolated by us from several locations in Mississippi in recent years. The race of the bacterium is primarily race 18 and not a new race. We have screened 52 varieties for resistance to the disease using a high pressure sprayer in field plots. Thirteen varieties were immune and eleven varieties had a high degree of resistance to the disease. The other twenty-three varieties were susceptible to very susceptible.

8:45 EVALUATION OF DIFLUBENZURON (DIMLIN[R]) TO CONTROL CERCOSPORA SOJINA, THE FROGEYE LEAFSPOT PATHOGEN OF SOYBEAN

C. Wells (1,2*), R.E. Baird (1), and G. L. Sciumbato (2), (1) Mississippi State University, Mississippi State, MS 39762 and (2) Delta Research and Extension Center, Stoneville, MS 38776

Diflubenzuron, a benzamine chitin-inhibitor commonly used as an insecticide, has been reported to have fungicidal activity in Mississippi against, Cercospora sojina, the frogeye leaf spot (fls) pathogen of soybean. Chemical applications for control of both insects and fls would result in reduced costs for soybean producers and less potentially harmful chemicals in the environment. To further investigate diflubenzuron's fungicidal activity, two field trials were established during the 2006 growing season in two locations in Mississippi. Within each trial, one determinate and one indeterminate variety were planted in a randomized complete block design with four replications per treatment. Four treatments consisting of diflubenzuron (2.0 and 4.0 oz/[R]), pyraclostrobin (Headline[R])(4.7 oz/A) and an untreated control were repeated, one set was artificially inoculated with C. sojina and one set using natural inoculum. Within the artificially inoculated plots, one set received inoculum 24 h prior to and one 24 h after chemical treatments. Disease ratings were performed two and four weeks after inoculation. Yield data were also recorded. The excessively dry environmental conditions in 2006 were unfavorable for disease development. Therefore, no significant differences in disease ratings or yield were seen between the eight treatments according to the Waller-Duncan K ratio [t.bar] Test at the P<0.05 level. Field trials will be repeated in 2007.

9:00 IDENTIFYING ISOLATES OF PHYTOPHTHORA CINNAMOMI FOR CHALLENGING BLUEBERRY (VACCINIUM sp.) CULTIVARS TO DEVELOP A GREENHOUSE SCREENING TECHNIQUE FOR IDENTIFYING RESISTANT BLUEBERRY GERMPLASM

Melinda Miller-Butler (1*), Kenneth J. Curry (1), and Barbara J. Smith (2), (1) University of Southern Mississippi, Hattiesburg, MS 39406 and (2) USDA-ARS Southern Horticultural Laboratory, Poplarville, MS 39470

The production of blueberries (Vaccinium sp.) in Mississippi, occupies over 2000 acres as of 2006. Phytophthora cinnamomi causes severe root rot on many woody plant species including blueberries. Soil samples were collected from symptomatic blueberry plants at several farms in Mississippi. Successful isolations were made using a floating leaf technique and placing the leaf pieces on media amended with antibiotics and fungicides. Unidentified isolates were confirmed with a Phytophthora-genus specific ELISA test. Known isolates of Phytophthora cinnamomi were obtained from an outside source. Seedlings with little or no resistance to phytophthora root rot were challenged with all isolates. Unidentified isolates causing premature senescence in the seedlings will be used to challenge young blueberry plants for developing a greenhouse technique to identify blueberry germplasm resistant or at least tolerant to phytophthora root rot. Ultimately this will lead to the development of resistant cultivars that offer a means of controlling this disease in commercial blueberry fields.

9:15 ESTABLISHMENT OF BLACKBERRIES AND DETECTION AND MANAGEMENT OF RASPBERRY CROWN BORER

Edward Heard, Frank Matta*, Blair Sampson, John Braswell, and Juan Silva, Mississippi State University, Mississippi State, MS 39762

Field evaluations of new tactics for early detection and management of raspberry crown borer, RCB, Pennisettia marginata (Harris) (Lepidoptera: Sesiidae) on blackberries, Rubus L. subgenus Rubus Watson, were performed at the Mississippi Agriculture and Forestry Experiment Station North Farm from December 2004 to July 2006. RCB is the primary limiting factor for blackberry production in Mississippi. Borer damage to canes and crowns underground can increase and go undetected until a crop is devastated by infestation. A randomized field plot with 3 adjacent rows was planted with infested blackberries and certified nursery stock of two recommended cultivars, thorny 'Chickasaw' and thornless 'Apache'. Insect pest management tactics targeting RCB included the following soil drenches: chemical insecticide bifenthrin, recently registered and labeled for RCB management; experimental pesticide E2Y45, being evaluated in association with USDA IR-4 Program; entomopathogenic nematodes Steinernema feltiae, beneficial organisms effective against several species of clearwing-borer moths including limited success against RCB. Before application of S. feltiae, unknown effects of pesticides on nematode viability and infectivity were evaluated in laboratory bioassays with late instar host greater wax moth larvae, Galleria mellonella (L.). Pesticides evaluated include the fungicides captan, pyraclostrobin + boscalid, lime-sulfur and the insecticide acetamiprid. Bioassays tested two entomopathogenic nematode species, S. feltiae and Heterorhabditis bacteriophora. Results indicated that lime-sulfur severely limited nematode movement and infectivity at 100% and 10% application rate. Pyraclostrobin + boscalid decreased movement of both nematode species and infectivity of S. feltiae at 100% and 10% rate. Lower rates are not significant. Methods for early detection of RCB include placement of sticky traps baited with variable amounts of insect pheromones (E,Z)313-octadecadien-1-ol and/or (E,Z)3-13-octadecadien-1-yl acetate at 4 sites within the plot.

9:30 BIOAVAILABILITY OF MERCERY IN SOIL AND WATER AND ITS EFFECTS ON PLANT STRUCTURE AND REFLECTANCE

Safwan Shiyab, Frank Matta*, F. X. Han, Yi Su, and D.L. Monts, Mississippi State University, Mississippi State, MS 39762

There is great concern regarding the clean up of toxic pollutants from the environment. Phytoremidiation is a process, environmentally friendly, and cost-effective to clean up heavy metals and the other toxic compounds from contaminated environments. Mercury contamination is ubiquitous in the Y-12 watershed of Oak Ridge, TN and has been identified as a key contaminate in soil, sediment, surface water, and ground water. The objectives of this study were to apply phytoremidiation to mercury contamination in soil and to study the phytoremidiation process, including metal uptake, complexation, and translocation by microscopy, chemical analysis, and spectral reflectance. Indian mustard (Brassica juncea), Long standing and Florida broadleaf were used to phytoremidiate soils contaminated with various forms of mercury (mercury chloride, mercury nitrate, mercury sulfide). Indian mustard had a high uptake capacity and translocation of Hg from contaminated soils. Physiological changes in Indian mustard plants due to uptake and accumulation of Hg were investigated. Result of this study indicate that Hg at higher concentrations had a profound impact on the physiology and internal structure of plants which in turn, affected the spectral reflectance. Leaves, stems and roots were harvested to study leaf anatomy and metal accumulation. The majority of Hg accumulated in the root and the remaining Hg was translocated to the shoot.

9:45 Break

10:00 ROOT AND FOLIAR RESPONSES OF MARIGOLD TAGETES PATULA, ZINNIA ZINNIA ELEGANS AND VINCA CATHARANTHUS ROSEUS GROWN IN 288 PLUG TRAYS COATED WITH ZINC CHLORIDE COMPOUNDS.

Frank Matta, Mississippi State University, Mississippi State, MS 39762

The objective of this research was to determine the effects of zinc chloride on root and foliar growth of three bedding plant species (Marigold Tagetes patula, Zinnia Zinnia elegans and Vinca Catharanthus roseus). Plug trays were treated with anhydrous zinc chloride at 0, 3.5, 7, and 14 percent using 2 separate paints as the source of zinc (white latex and athletic field marking paint). Plants were grown in a greenhouse at 85[degrees] F/65[degrees] F (day/night temperature) for 3 weeks. Plants were harvested and dried to obtain plant tissue analysis of accumulated nutrients. Nutrient levels were statistically analyzed to determine the level at which zinc chloride applications become phytotoxic. Results are reported.

10:15 MANAGEMENT OF HIGH PHOSPHORUS SOILS IN MISSISSIPPI: FORAGE PRODUCTION AND AGGREGATE STABILITY

Anserd Foster*, W.L. Kingery, and M.S. Cox, Mississippi State University, Mississippi State, MS 39762

In Mississippi there is a need for management of pasture land with elevated phosphorus levels. On pastures, offsite phosphorus movements may be reduced by improving soil structure via increased aggregate stability. A study was conducted to determine the influence of different forage systems on forage production and aggregate stability. Crops grown in study were "Jackson" annual ryegrass (RG) (Lolium multiflorum Lam.), "Kentucky 31" tall fescue (TF) (Festuca arundinacea Schreb.)," Redland Max" red clover (RC) (Trifolium pratense L.), "Chickasaw" white clover (WC) (Trifolium repens L.) and "Common" bermudagrass (BG) (Cynodon dactylon (L.). Cool season forage systems were TF+ Nitrogen (N), RG+N, TF+WC, TF+RC, RG+WC, RG+RC and warm season forage systems were BG +N, BG+WC and BG+RC. The soil used in the experiment was a Savannah silt loam with a 25-year history of poultry litter application. Forage yield was highest in BG compared to that of RG and TF systems. Aggregate stability measurements showed TF and RG systems with greatest percentage of stable aggregates. The results also suggested a decreasing trend in the percentage of stable soil aggregates with the combination of RC and WC and grasses. Phosphorus removal was highest in RG and BG systems. Our findings suggest that different forage systems will influence both forage production and soil aggregate stability on high-P soils in Mississippi.

10:30 PLANT DENSITY EFFECT ON YIELD AND BIOMASS DEVELOPMENT OF ORGANIC EGGPLANT (Solanum melongena L)

Sixto A Marquez*, Girish K Panicker, Om P Vadhwa, and Patrick Igbokwe, Alcorn State University, Lorman MS 39096

Eggplant (Solanum melongena L) is a native of India and is widely cultivated for its fruits in the southern United States. As a part of the conservation research being carried out on vegetable crops in Mississippi, a study was conducted to determine the plant density effects on yield and biomass development at various growth stages. A common cultivar Black Beauty was raised on Memphis Silt Loan soil (Typic Hapludalf, silty, mixed, thermic) at low density planting (LDP), 0.760 m x 0.912 m; and high density planting (HDP), 0.609 m x 0.912 m. Worm castings and composted cow manure were applied equally to each plant. No chemicals were sprayed on the crop. Destructive harvest studies were conducted at various stages of growth and analysis of variance was run. Plant height, rhizosphere width, and root length were higher for HDP compared with LDP. Total dry biomass, leaf area index (LAI) and yield were higher for LDP. There was no difference in canopy width, stem diameter, canopy cover and fruit length and diameter. LDP is more advisable for farmers because it was higher in yield, total dry biomass and LAI.

10:45 FATE OF FUNGAL SPORE INOCULA APPLIED TO STRAWBERRY LEAVES FOR FUNGICIDE SCREENING EXPERIMENTS

Maritza Abril (1), Kenneth J. Curry (1), and Barbara J. Smith (2), (1) University of Southern Mississippi, Hattiesburg, MS 39406 and (2) USDA-ARS Southern Horticultural Laboratory, Poplarville, MS 39470

Fungicide screening experiments for germplasm in strawberry and other plants are frequently conducted by spraying the plants with inocula composed of a spore suspension of the appropriate pathogenic fungus and scoring the plants for symptoms at a reasonable interval after the spraying. We have determined that spraying as a method of delivering inoculum results in a spore concentration on the leaf that is one order of magnitude less than the starting inoculum. We collected leaf runoff expecting to find the lost spores, but the runoff is also less concentrated than the original inoculum. We have subsequently devised a carefully controlled series of experiments in which the inoculum is delivered to a glass slide in very small, precisely measured volumes from which exhaustive counts can be taken and compared back to the initial inoculum. The loss of spores between the original inoculum and the slide is one order of magnitude just as with the leaf. We can confidently compare the leaf/spray and slide/direct inoculum experiments in order to determine the mechanism by which spores from the original inoculum are lost. We have traced the loss of spores back to the inoculating pipette where they form a thick crust on the inside of the pipette. The final step in our analysis will be a return to the spraying device to examine the delivery tube and the spray head itself. Understanding this loss of spores can contribute significantly to creating well-designed fungal screening experiments where a fungal inoculum must be delivered by spray.

11:00 THE EFFECTS OF PLOT SIZE AND MOWING HEIGHT ON PESTICIDE RUNOFF FROM MISSISSIPPI PRIDE BERMUDAGRASS (Cynodon dactylon [L] Pers. x Cynodon transvalensis Burtt-Davy

Peter Ampim (1*), J. H. Massey (1), B. R. Stewart (1), M. C. Smith (1), K. L. Armbrust (2), A. B. Johnson (3), and A. A. Andrews (1), (1) Mississippi State University, Mississippi State, MS 39762, (2) Mississippi State Chemical Laboratory, Mississippi State, MS 39762, and (3) Alcorn State University, Lorman, MS 39096 and

We investigated the effect of plot size on pesticide runoff from Mississippi Pride bermudagrass (Cynodon dactylon [L] Pers. x Cynodon transvalensis Burtt-Davy) maintained as golf course fairways and residential lawns on a hydrologic class D soil. The four plot sizes investigated were 1.8 x 1.8 m, 3.7 x 9.1 m, 6.1 x 24.4 m and 12.2 x 38.1 m. The plots had 3 % slope with minimal cross slope. The experimental design was a randomized complete block design with split plot arrangement of treatments. The main plot factor was plot size while the subplot factor was mowing height (1.5 and 5.0 cm). Following a standardized protocol, 2, 4-D herbicide, flutolanil fungicide and chlorpyrifos insecticide were co-applied at 1.12 kg ai/ha, 2.24 kg ai/ha and 2.24 kg ai/ha, respectively. A conservative tracer (KBr) was also separately applied at 15 kg/ha to allow tracking of water movement in the turfgrass systems. Simulated rainfall was applied at 38.1 mm/h to the plots 24 h after pesticide application. Pesticide concentrations in runoff and application monitors were analyzed by high performance liquid chromatography using UV-Vis detection. The limit of quantification for the three pesticides was approximately 10 ppb. Plot size and grass mowing height effects on pesticide runoff and several hydrological parameters will be discussed.

11:15 GRAZING PREFERENCE FOR BERMUDAGRASS CULTIVARS INTERSEEDED WITH CHICORY 

Vitalis Temu* and David Lang, Mississippi State University, Mississippi State, MS 39762

Bermudagrass (Cynodon dactylon L.) is a perennial, subtropical warm season grass that can be difficult to force animals to graze. Chicory (Cichorium intybus L.) is a highly palatable and nutritious forb. The objective was to determine if addition of chicory to bermudagrass would increase the acceptance of bermudagrass by grazing animals. Chicory was seeded into six replicated bermudagrass cultivars on 7 October 2005 that had been grazed by cows or steers (Bos taurus) during the previous five summers. Grazing preference among bermudagrass was observed by taking plate meter readings, height and herbage measurements before and after each grazing interval as well by visual estimation of the portion of each plot that had its leaves chewed or "grazed". Prior to planting chicory grazing preferences were observed to be the following order: 'Alicia' < 'McDonald' < 'Coastal' < 'Lott' < 'Tifton 44' = 'Sumrall'. There was a distinct difference with Alicia bermudagrass. It was not only grazed the least grazed but it was obviously rejected by cows or steers given a choice of bermudagrass cultivars. Addition of chicory in 2005 did not alter the grazing animal's preference among bermudagrass cultivars. Even though chicory is highly palatable it was also not readily grazed when it was growing in a bermudagrass cultivar that was not preferred by cattle, i.e in Alicia or McDonald. Chicory was readily grazed in bermudagrass plots that were heavily grazed by cattle, i.e. in Tifton 44 or Sumrall. There was a strong negative influence by the least grazed bermudagrass cultivars on chicory palatability. The addition of highly palatable chicory was not able to enhance palatability of bermudagrass.

FRIDAY AFTERNOON

Hunter Henry Ballroom B

1:15 PERFORMANCE EVALUATION OF NEW RYEGRASS VARIETIES AT ALCORN STATE UNIVERSITY: NUTRITIONAL VALUE, DRY MATTER, GROWTH AND MATURITY

Evelin J. Cuadra (1), Ricky Johnson (1), Jason Jones (1*), Bisoondat Macoon (2), and Victor Njiti (1), (1) Alcorn State University, Lorman, MS 39096 and (2) Brown Loam Experiment Station, Raymond, MS 39154

Ryegrass is perhaps the best quality forage grown for cattle feeding in Mississippi and the southern states. Nevertheless, it has the inconvenience that harvesting time for high quality ryegrass takes place during raining, cool and humid conditions. Therefore, evaluation of new varieties capable of maintaining a high nutritional quality over an extended season and into the early summer conditions is routinely performed. Thus, a study was conducted at Alcorn State University to evaluate 3 varieties, Passerel Plus (lolium multriflorum), Tetralite II (lolium hybridum), and Zorro (lolium multiflorum) for nutritional content and adaptability to early summer conditions in a Memphis silt loam soil. Seeds were planted in October of 2004 and, grass samples were collected every 4 weeks starting in February and through May of 2004; chemical analysis was performed after collection and drying of samples. Average monthly temperature and rain were also recorded. DM yield was higher for Passerel Plus (54340.1[+ or -] 182.3) when compared to Zorro (4086.2 [+ or -] 609); however, it did not show any difference with Tetralite II (4522.3[+ or -]405.3). The same trend was observed for TDN content (4087.9[+ or -]206.7; 3224.5[+ or -]510.5; 3513.6[+ or -]352), and NDF (2443.9[+ or -]39; 1817[+ or -]196.9; 2121.6[+ or -]127.5). There was no significant difference in CP between the three varieties. Nevertheless, a higher content in ADF was observed in Passerel Plus (1349.9[+ or -]32.6) when compared to Zorro (985.6[+ or -]108.7) and Tetralite II (1125.9[+ or -]66.6). Data was analyzed using the general linear model of SAS. Responses are reported as different at the P< 0.05 level. Means were separated using Duncan's multiple range test.

1:30 FACILITATING FUNCTIONAL GENOMICS ANALYSIS IN MISSISSIPPI: THE AGBASE DATABASE

Fiona McCarthy*, Nan Wang, Bindu Nanduri, Shane C. Burgess, and Susan M. Bridges, Mississippi State University, Mississippi State, MS 39762

Analysis of functional genomics (transcriptomics and proteomics) datasets is hindered in agricultural species because agricultural sequences have poor structural and functional annotation. To facilitate systems biology in these species we have established the curated, web-accessible, public resource "AgBase" (www.agbase.msstate.edu). We have improved the structural annotation of agriculturally important genomes by experimentally confirming the in vivo expression of electronically predicted proteins and by proteogenomic mapping. The de facto standard for functional annotation is Gene Ontology (GO) and we use the gene ontology to associate function with agricultural genes. Via the AgBase database we contribute GO annotations and provide a mechanism for researchers to request GO annotations or submit their own GO annotations. We have also established a two tier system of GO annotations for users. This system gives researchers the initial breadth required for functional modeling, leading to experiments that test the function of these gene products, which in turn leads to higher quality GO annotations. In addition to providing structural and functional annotation for agricultural species, AgBase also provides tools for functional analysis of proteomics and gene expression datasets. The tools are provided online and can be used individually or as components of a pipeline. The AgBase suite of tools has been used for functional modeling of both proteomics and gene expression datasets from chicken, maize, cow, and a number of microbes.

1:45 INHIBITION OF PPO ACTIVITY WITH ADDITIVES AND THEIR INFLUENCE ON ANTHOCYANINS EXTRACT IN RABBITEYE BLUEBERRY MASH

Jelena Stojanovic* and Juan Silva, Mississippi State University, Mississippi State, MS 39762

Antioxidant properties of blueberries are contributed by their high concentration of anthocyanins and phenolics that are readily destroyed by blueberry polyphenol oxidase (PPO). Inactivation of PPO by heating to 90?C for 1 min destroys blueberry antioxidant properties. Addition of PPO inhibitors in the maceration step may eliminate heat pretreatment Anthocyanins were extracted using acetone/chloroform and concentration determined using the pH differential method. Activity of PPO without and with presence of inhibitors was determined in citrate/phosphate buffer (pH = 3.6) using 4-methylcatechol as a substrate and monitoring change in absorbance at 420 nm. Disappearance of anthocyanins in presence of PPO and inhibitors was monitored at 520nm for 20 min. Activity of PPO was 3.36 Units/ml. Addition of 0.1% sodium benzoate decreased PPO activity to 0.48 U/ml. Other inhibitors reduced PPO activity with EDTA heaving the least influence (2.88 U/ml). Concentration of anthocyanins was 237mg/ml. Destruction of anthocyanins was most evident in the first 5 min with 20% loss. Sodium benzoate decreased that loss to only 10%. These results suggest that sodium benzoate would be the best choice as an inhibitor of PPO during the maceration treatment of blueberry mash. These findings can eliminate heat pretreatment allowing further pasteurization of juice with a nonthermal process.

2:00 SYSTEMS ANALYSIS OF PASTEURELLA MULTOCIDA RESPONSE TO SUB-MINIMUM INHIBITORY CONCENTRATIONS OF ANTIBIOTICS

Bindu Nanduri*, Mark Lawrence, and Shane C. Burgess, Institute for Digital Biology, Mississippi State University, Mississippi State, MS 39762

Antibiotic therapy is based on achieving a minimum inhibitory concentration (MIC) for a sufficient amount of time in the infected tissue. However, with antibiotic resistant bacterial strains, it may not be possible to achieve MIC in the target tissue and the only remaining therapeutic option could be treatment with a sub-MIC of antibiotic. In this study we evaluated sub-MIC antibiotic effects on a bovine respiratory pathogen Pasteurella multocida using systems approaches. P. multocida was grown in the absence or in the presence of a quarter MIC of amoxicillin, chlortetracycline and enrofloxacin that differ in their mode of action and the proteins were isolated, trypsin digested and analyzed by 2D-LC-ESI-MS/MS. The predicted proteome of P. multocida has 2015 proteins of which 996 were identified in our dataset. Non-isotopic quantification method was used to determine significant changes in protein expression in response to antibiotics. A total of 150, 122, and 114 proteins were differentially expressed in response to amoxicillin, chlortetracycline, and enrofloxacin, respectively. We mapped experimental data onto P. multocida protein interaction network using PathwayStudio (Ariadne genomics). All three antibiotics led to lowered expression of proteins involved in energy metabolism, DNA synthesis. Expression of DNA repair proteins recN, recA and recG increased in response to enrofloxacin, which is likely an adaptive response to the quinolone-mediated DNA replication block by double strand DNA break repair. We also identified key regulatory elements in the network (ddl with amoxicillin) whose expression could be modulated (gene knockouts, RNAi etc) for favorable use of sub-MIC antibiotics.

2:15 EFFECT OF COOKING AND PACKAGING METHODS ON CONSUMER ACCEPTABILITY AND SHELF-LIFE OF READY-TO-EAT GULF BROWN SHRIMP

V.V. Kamadia (1), M. W. Schilling (1), D. L. Marshall (1), L.S. Andrews (2*), and Y. Yoon (1), (1) Mississippi State University, Mississippi State, MS 39762 and (2) Mississippi State University, Biloxi, MS 39532.

The objectives of this study were to evaluate the influence of various cooking and packaging methods on consumer acceptability and shelf-life of ready-to-eat shrimp. Fresh Gulf of Mexico Brown shrimp (Penaeus aztecus, Medium) tails (shell-on) were individually quick frozen on the day of harvest and kept frozen until used. Shrimp (0.45 kg/treatment) were peeled and then cooked at three temperature and time combinations (63[degrees]C for15 s, 85[degrees]C for 5 min, and 93[degrees]C for 5 min) and packaged under air, carbon dioxide, and vacuum conditions. The samples were stored from 1 to 50 days at 2[degrees]C. Odors were evaluated using a nine point hedonic scale to determine consumer acceptability and descriptive sensory analysis to determine shelf-life. Agglomerative hierarchical clustering was utilized to group consumers together based on their preference of packaging treatment. Air, carbon dioxide, and vacuum packaged treatments had shelf-lives of 5-9, 20-25, and 20-30 days, respectfully, and the 63[degrees]C for 15 s cooking method had a shorter shelf-live than its 85 and 93[degrees]C counterparts for all packaging methods. On an average, vacuum packaged samples were liked moderately and were preferred (p<0.05) over samples packaged in carbon dioxide and air (liked slightly). Panelists were grouped into four consumer clusters in which greater than 70 % of consumers determined that all treatments were acceptable, with greater than 90 % acceptability in vacuum packaged samples. This reveals the potential to produce vacuum packaged Ready-to-eat shrimp if processed under conditions that will prevent ingestion of botulinum toxin.

2:30 AG ACADEMY: BUILDING AGRICULTURE IN THE HEARTS OF CHILDREN IN SOUTHWEST MISSISSIPPI

Gwendolyn D. L. Boyd, Alcorn State University, Alcorn State, MS 39096

Agriculture has become a high-tech, computerized world. The study of Agriculture is not just about farming anymore. A bachelor's, masters', or even a doctorate in Agriculture can give students the opportunity to become a biosystem engineer, a plant pathologist, or even an animal scientist. Students may work for governmental agencies, private sectors, seed companies, floriculturist, landscaper, agricultural economist, sales representative, or go into private practice. There are so many ways to combine Agriculture with just about anything. AG ACADEMY is a program designed to education children in Southwest Mississippi about the importance of Agriculture. The children get the opportunity to see Agriculture first hand. They learn about flowers, soil, money, plants, trees, water, animals, and clothing. All of these things are directly associated with Agriculture. The ages of this academy ranges from 6-9. The reason for this age group is to encourage the interest in Agriculture before their mind is set to other sciences or other disciplines. Agriculture is a dying discipline, and this is one way to bring life to Agriculture. Exposing young minds to the various educational aspects of Agriculture with help ensure a future generation of forest managers, forest rangers, veterinarians, horticulturists, plant pathologjsts, farmers, botanist, and other Agricultural-related professionals.

3:00 Divisional Poster Session

Location: Bost Auditorium North

POSTHARVEST APPLICATION OF ANTIMICROBIALS IN CATFISH-A REVIEW

Bang-Yuan Chen*, Juan Silva, and Taejo Kim, Mississippi State University, Mississippi State, MS 39762

Catfish as other fish muscle has a structure low in collagen and high in protein/amino acids that makes it very easy for microbial attachment and growth. Fresh catfish production accounts for one third of sales, requiring long shelf life to compensate for long distribution distances and retail case duration. After harvesting, catfish can be contaminated by processing equipment, surfaces and solutions. In order to enhance keeping quality, catfish should be processed rapidly; temperature should be decreased rapidly, and held at low temperature. Ice helps maintain the temperature of the fish low but it also melts and contributes to microbial growth. Antimicrobials added during processing or after can aid in maintaining optimum quality and extending shelf life of catfish. Some of the antimicrobials studied include chlorine based compounds, acids, oxidizers, salt, irradiation, natural or derived substances, and combinations in conjunction with packaging. The effectiveness of antimicrobials varies according to microflora, growth stage, and conditions of the fish. Single antimicrobial treatment can result in 0.4 to 1.0 log CFU reduction. Combination treatments can result in over 2 log CFU reduction, resulting in an extended shelf life. In addition. antimicrobials can have different impacts on catfish appearance and odor. Therefore, the choice of antimicrobial and the quality of catfish needs to be considered.

CHARACTERIZATION OF THE AROMA IMPACT COMPOUNDS OF FISH SAUCES BY GC-MS BASED ON SPMEOSME-GCO WITH DILUTION METHODS

Y. Yoon, A. J. Pham, M. W. Schilling, V.V. Kamadia, and D. L. Marshall, Mississippi State University, Mississippi State, MS 39762

The objectives of this study were to characterize volatile compounds and to determine aroma impact compounds in various fish sauces using gas chromatography coupled with an ion trap mass selective detector (GC-MSD) and a solid phase microextraction-OSME-gas chromatography olfactometry (SPME-OSME-GCO) technique that was coupled with dilution methods. This methodology was also utilized to determine the relationship between sample concentration and odor intensity using Stevens' Power Law. Aroma impact compounds that were present in all four fish sauce samples included 3-methyl-2-butanamine (fishy), butanoic acid (pungent or dirty socks), dimethyl pyrazine (buttery popcorn), and benzaldehyde (sweet and cotton candy). Based on the results of this study, it is apparent that SPME-OSME-GCO with serial dilutions is a rapid technique with very little sample preparation that can be utilized to differentiate between aroma intensities and impact compounds in foods that contain both a high concentration of water and aroma compounds. SPME-OSME-GCO coupled with serial dilution methods also revealed the potential for the determination of Stevens' exponents for key odorants in four fish sauces.

SANITATION TREATMENT TO DECREASE MICROBIAL LOAD OF PROCESSING BLUEBERRIES

Wei-Chun Chen* and Juan Silva, Mississippi State University, Mississippi State, MS 39762

Processing blueberries are washed prior to freezing and storage. The wash treatment can serve as a partial sanitation treatment. Southern blueberries can have high counts of bacteria and yeast and molds due to high humidity and temperature. Some of these blueberries are used in unheated products like yogurt. The market is demanding lower microbial counts in order to prevent spoilage of further-processed products made with them. The objective of this study was to evaluate some sanitation treatments on blueberry microbial load. The blueberries were divided into fresh and frozen (-20C for seven days). The berries were subject to a 30 sec dip with each of the treatments, followed by draining. Microbial load was determined by massaging in peptone buffer at a 1:10 dilution. Chlorine at 400 ppm lowered APC by 2-3 log CFU/g and YMC by only less than 1 log. Other treatments such as 200 ppm chlorine, a fungicide, and water were not effective. Acidified sodium chloride at 600 ppm for 30 sec was effective, lowering APC and YMC to below detectable levels. These results were similar for fresh and frozen fruit. Panelists did not detect any differences between the treated and untreated samples.

CADMIUM BIOACCUMULATION IN COLLARD AND INDIAN MUSTARD PLANTS

M. Zaman*, Cherry N. Lockett, Cynthia A. Addae, Shenika B. Poindexter, and Brandon J. Riley, Alcorn State University, Lorman, MS 39096

The tolerance of Brassica oleracea var: viridis L. (Collard) and Brassica juncia (Indian Mustard) plants to soil cadmium (Cd) and bioaccumulation of Cd in plant tissues were evaluated. Plants were grown in the laboratory under color corrected lights in soils containing 0 ppm, 250 ppm, 500 ppm, and 1000 ppm Cd. Plants were harvested on day 30 of the experiment. Dried plant samples were acid digested for tissue Cd analysis. Tissue Cd analysis was performed using an atomic absorption spectrophotometer. Data were analyzed for biomass production and tissue Cd accumulation. Results indicated that B. juncia plants were able to tolerate higher Cd concentration in soil as compared to B. oleracea plants. And bioaccumulation of Cd was dose related. Plant biomass was greatly reduced in some Cd treated plants. B. oleracea plants treated with 500 ppm and 1000 ppm Cd, did not survive the metal toxicity. Overall data indicated that B. juncia is a better Cd accumulator as compared to B. oleracea and can be used for remediation of Cd contaminated soil.

RAPID PURIFICATION OF INTERNALIN B FOR DETECTION OF LISTERIA MONOCYTOGENES

Taejo Kim (1*), Y. S. Jung (1), Juan Silva (1), and Supanee Danviriyakul (2), (1) Mississippi State University, Mississippi State, MS 39762 and (2) Chandrakasem Rajabhat University, Bangkok, Thailand

Conventional immunological methods for the detection and identification of bacteria in food are greatly restricted by initial enrichment (up to 24h) for detection of pathogens, including Listeria monocytogenes, which are initially present in low numbers. Sensitivity and specificity of antibodies are critical for immunodetection of biomolecules in antibody-based assay. Since clinical and food strains of L. monocytogenes express InternalinB (In1B) without polymorphism, it could be a good candidate as a protein marker to detect Listeria monocytogenes. Listeria grayii and Listeria innocua did not express In1B without in1B gene while all tested Listeria monocytogenes possess in1B gene and expressed In1B. Listeria monocytogenes 19115 had the lowest band intensity, which required an enrichment step of In1B. Spin-ion exchange chromatography was a simple and rapid method to enrich and purify In1B within 20 min. This study suggests that rapid purification of In1B could be used as a rapid and sensitive detection method of Listeria monocytogenes.

BRINE ABSROPTION AND RETENTION IN CATFISH FILLET STRIPS

Youkai Lu, and Juan Silva*, Mississippi State University, Mississippi State, MS 39762

Liquid absorption and retention are important in fresh muscle foods processing. The objectives of this research were to study the diffusion and retention of brine solution in fresh catfish strips and its influence on their sensory profile. Fresh catfish strips were immersed in either 2% (2B) or 1% (1B) brine ice slurry solutions or tap water (0B) ice slurry solution (1:1 ratio of water to ice) for up to 24 hours. They were then tested for liquid absorption, while retention was measured after 24 h in refrigerated storage. Fillet strips immersed in 2B absorbed the same amount of liquid than strips immersed in tap water ice slurry solution, but they lost only one fourth of the absorbed water/brine in the following 24 h refrigerated storage, about one third less than those in fillets strips immersed in either 1% brine ice slurry or tap water ice slurry solution. As immersion time beyond 8 h increased, absorption increased. The maximum absorption rate occurred in the first 4 h immersion, with the rate abruptly decreasing thereafter. Compared to the OB, strips immersed in 1B neither promoted absorption nor enhanced retention. Even though 2B did not promote water/brine absorption, it did enhance water/brine retention. The 2% brine extracted more proteins and resulted in a slimy appearance on the fillet surface. Brine chilled fish enhanced overall flavor, enhanced juiciness, tenderness and improved mouthfeel of baked fillet strips.

EFFECT OF EXOGENOUS JASMONIC ACID APPLICATION ON Aspergillus flavus KERNEL INFECTION AND AFLATOXIN PRODUCTION IN TWO MAIZE HYBRIDS (Zea mays L.)

Leigh Hawkins (1*), Dawn S. Luthe (2), Gary L. Williams (3), and W. Paul Williams (3), (1) USDA-ARS, (2) Pennsylvania State University and (3) United States Department of Agriculture 

Jasmonic acid (JA), produced by the octadecanoid pathway, is a phytohormone that triggers induced resistance against certain pathogens and arthropod herbivores. The octadecanoid pathway has been implicated in playing a role in the Aspergillus flavus-maize seed interaction. In field studies, the effect of exogenous applications of nonphytotoxic levels of JA at 8 and 13 days after midsilk were evaluated in two maize hybrids differing in resistance to A. flavus infection (Mo18W x Mp313E and GA209 x Mp339) for any effect on kernel infection by A. flavus, subsequent aflatoxin accumulation and a natural infection of Fusarium verticillioides. As a parent in single crosses, Mp313E has been effective in reducing aflatoxin contamination levels in other studies. An application of 71.5 ig JA x [plant.sup.-1], whether applied topically to silks or injected directly into the side of the ear, did not have a significant effect on reducing aflatoxin production. There were significant differences in aflatoxin accumulation and kernel infection by A. flavus and F. verticillioides between the two hybrids. GA209 x Mp339 tended to have higher levels of A. flavus kernel infection (7%) and aflatoxin (477 ng x [g.sup.-1]); yet, lower levels of F. verticillioides (14%) than Mo18W x Mp313E with 2% A. flavus kernel infection, 145 ng x [g.sup.-1] aflatoxin, and 26% F. verticillioides infection. This concentration of jasmonic acid is ineffective in reducing A. flavus kernel infection and aflatoxin accumulation in an agronomical setting.

MISSISSIPPI MASTER GARDENER TRAINING CURRICULUM COMPACT DISC: A MULTI-DISCIPLINE TWO-YEAR PROJECT

Lelia Kelly* and Julie Sexton, Mississippi State University Extension Service, Mississippi State, MS 39762

The Master Gardener program is one of the most popular and effective Extension programs. Budget cutbacks and a decreasing pool of personnel have warranted a reappraisal of how Extension trains these volunteers. The purpose of this project was to develop an up-to-date, complete, user-friendly, training program that could be used by agents or selected Master Gardeners with a minimum of training and advance preparation. Eleven subject matter specialists, 35 Extension agents, hundreds of Master Gardeners, and three curriculum specialists were involved in this project. In addition to updating of material a sampling of objectives that were addressed in the process follows: (1) format the curriculum into a lesson plan with step-by-step instructions; (2) remove all questionable copyrighted pictures, graphs, drawings, etc.: (3) align the student manual to the material presented in the PowerPoint lessons; (4) incorporate a resource list of hands-on activities to support each lesson; (5) provide a reference list for each lesson; (6) provide a standardized test with answer key for curriculum; (7) place the entire training curriculum on a compact disc. This project was completed in the summer of 2005. Publication and copyrighting of a compact disc which represented the training resources for the Master Gardener program was a first for Mississippi State University Extension Service.

MONITORING HENNEGUYA ICTALURI INFECTION IN CHANNEL CATFISH, BLUE CATFISH AND CHANNEL X BLUE BACKCROSS HYBRIDS USING HISTOPATHOLOGY, REAL-TIME PCR AND IN SITU HYBRIDIZATION 

Matt J. Griffin (1*), David J. Wise (2), and Linda M. Pote (1), (1) Mississippi State University, Mississippi State, MS 39762, and (2) Mississippi Agricultural and Forestry Research Station, Thad Cochran National Warmwater Aquaculture Center, Stoneville, MS 38776

Proliferative gill disease (PGD) caused by the myxozoan parasite Henneguya ictaluri is one of the most devastating parasitic infections in channel catfish aquaculture. Currently, there is no effective treatment for H. ictaluri and outbreaks can result in >50% mortality in catfish. Challenge studies have shown that blue catfish (Ictalurus furcatus) exposed to H. ictaluri exhibit a less severe inflammatory response and significantly lower mortalities than channel catfish. Using histopathology, real-time PCR (QPCR) and in situ hybridization (ISH) we observed the development and proliferation of H. ictaluri in channel catfish, blue catfish and channel x blue catfish backcross hybrids to elucidate factors attributing to the variation in host response. Sixty fish of each species were held in floating net pens and placed in a commercial catfish pond experiencing a clinical outbreak of PGD. Fish from each species (n=15) were sampled on days 1, 3, 5, and 7, and gills were examined for chondrocytic lysis and gross manifestation of the disease. Gill clips (~40-80 filaments) were taken for DNA analysis (QPCR) and whole gills were formalin fixed and processed for H & E staining and ISH. Our study showed H. ictaluri development and proliferation in all three species but confirmed channel catfish and channel x blue catfish hybrids experience a more damaging inflammatory response to H. ictaluri than observed in blue catfish.

CHELATE-MEDIATED CHANGES IN METAL SOLUBILITY AFFECT UPTAKE AND TRANSLOCATION OF CADMIUM BY WHEAT (TRITICUM AESTIVUM L.): IMPLICATIONS IN THE PHYTOREMEDIATION OF METAL-CONTAMINATED SOIL

Jennifer Ntoni*, Maria Begonia, Gregorio Begonia, Gloria Miller, and Juanquina Thomas. Jackson State University, Jackson, MS 39217

Phytoextraction is a cost-effective and environmentally friendly phytoremediation strategy for reducing toxic metal levels from contaminated soils. We hypothesized that the addition of synthetic chelates can increase the amount of bioavailable metal for root uptake, thereby improving the efficacy of phytoextraction. This study was conducted to determine whether the addition of synthetic chelates can enhance the root uptake and subsequent translocation of cadmium (Cd) to the shoots. Wheat (Triticum aestivum L. cv TAM-109) seeds were planted in plastic tubes containing topsoil and peat spiked with various levels (0, 250, 500 mg Cd/kg dry soil) of cadmium nitrate. At eight weeks after emergence, aqueous solutions (0, 250, 500 mg/kg dry soil) of [ethylenebis (oxyethylenenitrilo)]tetraacetic acid (EGTA) alone or in combination with acetic acid (HAc) were applied to the' root zone. Plants were harvested at 5 days after chelate addition to coincide with the duration of maximum Cd availability as determined from a corollary chelate-induced metal solubility study. Results revealed that wheat was tolerant to treatment combinations of Cd and chelates as shown by non-significant differences in root and shoot biomass among Cd/chelate-treated plants. Enhancements in root Cd uptake were attributed to chelate amendments especially at the highest Cd treatments. However, partitioning of the metal to the shoots was not significantly enhanced with chelate addition. This study demonstrated that the efficacy of phytoextraction can depend on the mobility of the metal in the soil especially at the growth stage when the plants have attained maximum biomass.

OPTIMIZATION OF FERMENTATION MEDIUM AND CONDITIONS FOR MYCELIAL GROWTH AND WATER-SOLUBLE EXO-POLYSACCHARIDES PRODUCTION BY ISARIA FARINOSA B05

Peng Wang (1*), Xiaolu Jiang (2), Yanhua Jiang (3), Huey-Min Hwang (1), and Xiaoke Hu (1), (1) Jackson State University, Jackson, MS 39217, (2) Ocean University of China, and (3) Yellow Sea Fisheries Research Institute, China

Isaria farinose is an entomogenous fungus which has been regarded as a popular and effective folk medicine for a long time because they can treat many diseases such as hepatitis, hypercholesterolaemia, hypertension and gastric cancer. Polysaccharides, the maximal metabolites of entomogenous fungi, have been demonstrated lots of biological activities such as immunostimulating, antioxiditive, and antitumor activities. In this experiment, the optimal fermentation medium and conditions for mycelial growth and water-soluble exo-polysaccharides production by Isaria farinose B05 were investigated. The medium components and fermentation conditions were optimized according to the one-at-a-time method, while the concentration of medium components was determined by orthogonal matrix method. The results showed that the optimal fermentation medium was as follows: sucrose 3.5% (w/v), peptone 0.5%, yeast extract 0.2%, [K.sub.2]HP[O.sub.4] 0.1% and MgS[O.sub.4] 0.05%. The suitable fermentation conditions were as follows: initial pH 7.0, temperature 25[degrees]C, medium volume 75 ml/250 ml, inoculum volume 5% (v/v), time 5 d. In such optimal nutrition and environmental conditions, the maximal mycelial yield was 2.124g/100ml after 4 d's fermentation, while maximal water-soluble exo-polysaccharides production reached 2.144 g/l after 5 d's fermentation. Key word: Isaria farinosa B05; optimization; submerged fermentation; exo-polysaccharides Acknowledgement: This research was supported in part by DOE grant# DE-FG3605G0852002/07-08-001

GENETIC RESISTANCE TO SALMONELLA IN CHICKENS: A PROTEOMIC PUZZLE

Bart H. J. van den Berg (1*), Susan J. Lamont (2), and Shane C. Burgess (3), (1) Mississippi State University, Mississippi State, MS 39762, Iowa State University, Ames, IA 50011, and (3) Digital Biology, Mississippi State University, Mississippi State, MS 39762

Despite current control methods Salmonella enteritidis (SE) infections in poultry remain a primary cause of human food-borne disease and a cost to poultry production. Evidence for genetic SE resistance in chickens exists, but the genetic mechanisms are unknown. We aim to identify and model differentially expressed proteins related to genetic resistance/susceptibility to SE. This will allow molecular genetic selection of resistance alleles as a novel means of SE control. We used proteomics to identify and model the differentially expressed gene-products in SE treated chicken lines. Two F8 intercross chicken lines (Leghorn and Fayoumi) were inoculated with SE and after 7 dpi, birds in the highest and lowest 10th percentile of the SF. burden distribution were identified. The spleens of high burden (HB) and low burden (LB), as well as non-treated control spleens, were removed and frozen. The proteomes from 9 spleens (3x high, 3x low and 3x control) for each genetic line were identified by DDF-MuDPIT. Quantitative comparisons between the groups were done using our ProteinMapper computational tool. Statistical analyses included ANOVA with Bonferoni correction to identify differentially expressed proteins. From the Fayoumi line, we identified 2179, 2647 and 2687 proteins for control, high and low, respectively. From the Leghorn line, we identified 1914, 1797 and 2572 proteins for control, high and low, respectively. The results of this analysis will be discussed both in terms of biomarkers for SE control in chickens and also for using chicken as a pathogenesis model of human salmonellosis.

DETECTION AND DISTRIBUTION OF GEOSMIN IN CHANNEL CATFISH TISSUE USING SPME/GC/MS

Ryan J. Poythress (1), Justin E. James (3)*, William E. Holmes (2), and Juan Silva (3), (1) Johnson Service Group, Knoxville, TN 37922, (2) Mississippi State Chemical Laboratory, Mississippi State, MS 39762, and (3) Mississippi State University, Mississippi State, MS 39762

The off-flavor of catfish is due to two compounds, geosmin and 2-methylisoborneol which cause an estimated $23 million loss to producers annually. Detection of this compound could be cumbersome in a complex matrix like fish. The objective of this study was to see the efficacy of using solid phase microextraction coupled with gas chromatography/mass spectrometry to study the distribution of the off-flavor in the fish. Whole fish was harvested from a pond that had detectable levels of geosmin. The fish was divided into 11 sections, from the anterior to the posterior part. Samples from each section were taken and placed into vials (2 and 4 g in each). SPME was used for volatile sequestration. Prior to extraction, the fiber was conditioned for 30 min in the injection port of the GC at 250[degrees]C. The fiber was allowed to absorb for 30 min at 60[degrees]C. The fiber was allowed to desorb for 3 min at 240[degrees]C in the injection port of the gas chromatograph. A Varian 3400 GC with helium as a carrier gas passing through a Phenomenex ZB5 (30m x 0.25mm, with a 0.25[micro]m film) coupled with the Varian Saturn 2000 GC/MS with wave board technology, which has the NIST library installed and used for identification. Muscle in the peritoneal cavity contained 3-5X higher amount of geosmin than other parts. This suggests that this part of the catfish should be sampled when screening for off-flavor.

ENHANCING PHYTOEXTRACTION: THE EFFECTS OF ACIDIFICATION AND CHELATING AGENTS ON THE BIOAVAILABILITY, UPTAKE AND TRANSLOCATION OF LEAD BY COFFEEWEED (SESBANIA EXALTATA RAF.)

Gloria Miller*, Maria Begonia, Gregorio Begonia, Jennifer Ntoni*, Katrina Dunn, and KaShiris Walton, Jackson State University, Jackson, MS 39217

Phytoextraction has emerged as a cost-effective and environmentally benign phytoremediation alternative for reducing toxic metal levels from contaminated soils. We hypothesized that the efficacy of phytoextraction can be increased through chelate amendments. This study was conducted to a) evaluate the suitability of coffeeweed [Sesbania exaltata Raf] as one of the potential crop rotation species for phytoextraction, and b)determine whether the addition of ethylenediaminetetraacetic acid [EDTA] alone or in combination with acetic acid [HAc] can enhance the phytoextraction of lead [Pb]. Seeds were planted in plastic tubes containing top soil and peat spiked with various levels [0, 1000, 2000 mg Pb/kg dry soil] of lead nitrate. At seven weeks after emergence, aqueous solutions [0, 1000 mg/kg] of EDTA and HAc were applied to the root zone. Plants were harvested at 6 days after chelate addition to coincide with the duration of maximum metal availability as determined from a corollary chelate-induced Pb solubility study. Results showed that coffeeweed was tolerant to moderate levels of Pb and chelates as shown by very slight reductions in root and no discernable effects on shoot biomass respectively. Root Pb concentrations increased with increasing levels of soil-applied Pb. Further increases in root Pb concentrations were attributed to chelate amendments. Translocation index was significantly enhanced with chelate addition especially when both EDTA and HAc were used. This study demonstrated that chelates can be added when phytoextractive plants have attained maximum biomass, then harvested less than a week later in order to improve phytoextraction efficacy.

ANTAGONISTIC EFFECT OF YOGURT LACTIC ACID BACTERIA AGAINST ENTEROBACTER SAKAZAKII THROUGH A SIMULATED GASTROINTESTINAL SYSTEM

Wei-Lien Weng* and Juan Silva, Mississippi State University, Mississippi State, MS 39762

Lactic acid bacteria are known to exhibit antagonistic activity against human pathogens and also maintain healthiness of the gastrointestinal system. Recently, Enterobacter sakazakii has been implicated in foodborne outbreaks, causing meningitis and enteritis. Since one portal of entry for Enterobacter spp. can be the gastrointestinal tract, yogurt lactic acid bacteria may exert an inhibitory effect on this pathogen. The objective of this research was to investigate the antagonism effect of commercial yogurt on E. sakazakii Fec39 through a simulated gastrointestinal system. Viable cell counts were determined on MRS and trypticase soy agar plates every hour of simulated gastrointestinal system. When an initial concentration of E. sakazakii as high as 108CFU/ml was used, both viable lactic acid bacteria and E. sakazakii counts were reduced by about 6-log during a three hour incubation in the gastric compartment. The counts increased to 106-107 CFU/m in the intestinal compartment after nine hours. But, when 104 ~105CFU/ml of E. sakazakii was initially applied to the simulated GI system; there was very little recovery of E. sakazakii in the intestinal compartment. Our results indicate that high amounts of yogurt lactic acid bacteria might have potential antagonistic effect on E. sakazakii in a simulated gastrointestinal system.

4:00 Divisional Business Meeting

Location: Hunter Henry Ballroom B