The Effect of Increasing Carbohydrate Concentrations on Expressed Intracellular and Extracellular Proteins by the Photorhabdus luminescens Bacterium and the Relative Bioluminescent Output

UNCP Author/Contributor (non-UNCP co-authors, if there are any, appear on document)
Joshua Cade (Creator)
The University of North Carolina at Pembroke (UNCP )
Web Site:
Devang Upadhyay

Abstract: Photorhabdus luminescens is a Gram-negative, pigment-producing enteric bacterium, bioluminescent and pathogenic to insects, with the capability to undergo phase variation. P. luminescens is symbiotically associated with the soil-dwelling nematode, Heterorhabditis bacteriophora, while also playing a crucial role in the reproduction cycle of this nematode. The phase I variant of P. luminescens produces light energy in the form of bioluminescence, the red anthraquinone-derived pigment, a symbiotic trait infective juveniles of H. bacteriophora exploit to attract insect hosts. The current study examined the effects of different carbohydrates at various concentrations on the growth of the P. luminescens phase I variant and the production of bacterial luminosity in liquid culture, while also examining the relative amounts of expressed extracellular and intracellular proteins. In this study, 2x Nutrient broth was used as a liquid growth media. Bioluminescence was measured with a Modulus™ single tube luminometer (Turner Biosystems) and reported in terms of relative luminosity units (RLU). Protein assays were performed using a spectrophotometer (Beckman™ DU640) set at a wavelength of 595nm, while utilizing Bradford dye. Bacterial growth density was also measured at 600 nm using a spectrophotometer (Beckman™ DU640). The carbohydrates utilized in the study of expressed extracellular and intracellular proteins were trehalose, cellobiose and d-sucrose, at 1, 3, 5 and 7 %. Overall bioluminescence and absorbance data utilized samples grown in varying concentrations of D-sucrose, Cellobiose, and Trehalose. The concentrations were varied from 1 % to 7 %.

Additional Information

Honors Project
Esther G. Maynor Honors College
Language: English
Date: 2020
Microbiology, Entomopathogenic Nematodes, Bacterial density, Soil-dwelling bacteria

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