Publications by authors named "Denise Caldwell"

Tar spot, a disease caused by the ascomycete fungal pathogen , is considered one of the most significant yield-limiting diseases of maize () within the United States. may also be found in association with other fungi, forming a disease complex that is thought to result in the characteristic fisheye lesions. Understanding how colonizes maize leaf cells is essential for developing effective disease control strategies.

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Background: Environmental stress due to climate or pathogens is a major threat to modern agriculture. Plant genetic resistance to these stresses is one way to develop more resilient crops, but accurately quantifying plant phenotypic responses can be challenging. Here we develop and test a set of metrics to quantify plant wilting, which can occur in response to abiotic stress such as heat or drought, or in response to biotic stress caused by pathogenic microbes.

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A major challenge in global crop production is mitigating yield loss due to plant diseases. One of the best strategies to control these losses is through breeding for disease resistance. One barrier to the identification of resistance genes is the quantification of disease severity, which is typically based on the determination of a subjective score by a human observer.

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Plant diseases caused by soilborne pathogens are a major limiting factor in crop production. Bacterial wilt disease, caused by soilborne bacteria in the Ralstonia solanacearum Species Complex (Ralstonia), results in significant crop loss throughout the world. Ralstonia invades root systems and colonizes plant xylem, changing plant physiology and ultimately causing plant wilting in susceptible varieties.

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Plant disease limits crop production, and host genetic resistance is a major means of control. Plant pathogenic Ralstonia causes bacterial wilt disease and is best controlled with resistant varieties. Tomato wilt resistance is multigenic, yet the mechanisms of resistance remain largely unknown.

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High-throughput phenotyping platforms for growth chamber and greenhouse-grown plants enable nondestructive, automated measurements of plant traits including shape, aboveground architecture, length, and biomass over time. However, to establish these platforms, many of these methods require expensive equipment or phenotyping expertise. Here we present a relatively inexpensive and simple phenotyping method for imaging hundreds of small- to medium-sized growth chamber or greenhouse-grown plants with a digital camera.

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Foodborne illness is an ongoing problem worldwide and is caused by bacteria that invade the food chain from the farm, slaughter house, restaurant or grocery, or in the home and can be controlled by strategies using biocides (antiseptics and disinfectants). Susceptibility profiles were determined for 96 Campylobacter jejuni strains obtained in 2011-2012 from broiler chicken house environments to antimicrobials and disinfectants as per the methods of the Clinical and Laboratory Standards Institute and TREK Diagnostics using CAMPY AST Campylobacter plates. Low prevalence of antimicrobial resistance was observed in C.

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is a bacterium that causes major diarrheal disease worldwide and is also one of the top five foodborne pathogens encountered in the United States. Poultry is a major source of , and a high-risk factor for contracting campylobacteriosis. Organic acids are used in the United States during food animal processing for removal of bacterial contamination from animal carcasses.

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Mechanically separated chicken (MSC) may be incorporated into other further processed foods, and has been identified as a transmission vehicle in human foodborne disease outbreaks involving the pathogen Salmonella enterica. Chickens possess pneumatic bones producing marrow, which may become infected with Salmonella and present a mechanism for Salmonella contamination of MSC. The primary objective of the current study was to ascertain whether chicken bone marrow was susceptible to Salmonella infection as a function of pathogen challenge method.

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Observing pathogen colonization and localization within specific plant tissues is a critical component of plant pathology research. High-resolution imaging, in which the researcher can clearly view the plant pathogen interacting with a specific plant cell, is needed to enhance our understanding of pathogen lifestyle and virulence mechanisms. However, it can be challenging to find the pathogen along the plant surface or in a specific cell type.

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Transport coops are infrequently washed and have been demonstrated to cross-contaminate broiler carcasses. We hypothesized that peracetic acid or a chlorinated cleaner, commonly used within poultry processing plants, can also be used to disinfect transport coops when applied via a compressed air foam system (CAFS). A mixture of fresh layer manure and concentrated Typhimurium (ST) was evenly applied to the floors of four pre-cleaned transport coops and allowed to dry for thirty minutes.

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Ralstonia solanacearum is the causal agent of bacterial wilt and infects over 200 plant species in 50 families. The soilborne bacterium is lethal to many solanaceous species, including tomato. Although resistant plants can carry high pathogen loads (between 10 and 10 CFU/g fresh weight), the disease is best controlled by the use of resistant cultivars, particularly resistant rootstocks.

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A monoclonal antibody (Mab) developed against a partially purified bursal protein extract was found to bind specifically to a single cell type in the cortico-medullary border region of the chicken bursa of Fabricius. These cells were microscopically similar to the bursal secretory dendritic-like cells. A product with an apparent molecular weight of approximately 56 kDa on SDS-polyacrylamide gel electrophoresis was immunopurified from bursal extracts by utilizing this Mab.

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