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You searched for +publisher:"Texas Tech University" +contributor:("Hamood, Abdul"). Showing records 1 – 2 of 2 total matches.

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Texas Tech University

1. Chalise, Nishant. Studies of an iron-regulated bacteriocin-like substance in Aeromonas sp.

Degree: MS, Biology, 2012, Texas Tech University

Aeromonas is a ubiquitous aquatic bacterium that causes serious infections in both cold- and warm-blooded animals, including humans. Various researchers have reported the production of an inhibitory substance that shows antimicrobial activity against different indicator bacteria. Here we present a case where an environmental isolate of Aeromonas salmonicida, designated as Aeromonas strain 92, produces a bacteriocin-like substance (BLS) that is negatively regulated by the presence of iron. Various properties associated with Aeromonas strain 92 BLS were determined and its proteinaceous nature was established. The bacteriocidal/bacteriostatic mode of action of BLS against the indicator bacterium Serratia marcescens was successfully demonstrated. A sodium dodecyl sulfate – polyacrylamide gel electrophoresis (SDS-PAGE) analysis between high-iron and low-iron culture conditions and Matrix Assisted Laser Desorption Ionization – Time Of Flight (MALDI-TOF) MS/MS analysis determined that BLS is likely to be the AsaP1 protein, a metallo-endopeptidase. This protein is highly expressed during the low-iron condition and displays antimicrobial activity against several different indicator bacteria. The gene encoding AsaP1 was ligated into the pBAD202 vector and was successfully transformed into Escherichia coli competent cells. The total lysate of a transformant shows antimicrobial activity against the indicator bacterium, but the expression of recombinant AsaP1 protein under L-arabinose induction couldn’t be verified by SDS-PAGE. Advisors/Committee Members: Hamood, Abdul N (committee member), Zak, John C (committee member), Jeter, Randall M. (Committee Chair).

Subjects/Keywords: Aeromonas; Bacteriocin; Antimicrobial; SDS-PAGE; MALDI-TOF; AsaP1; Metalloendopeptidase

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Chalise, N. (2012). Studies of an iron-regulated bacteriocin-like substance in Aeromonas sp. (Masters Thesis). Texas Tech University. Retrieved from http://hdl.handle.net/2346/73906

Chicago Manual of Style (16th Edition):

Chalise, Nishant. “Studies of an iron-regulated bacteriocin-like substance in Aeromonas sp.” 2012. Masters Thesis, Texas Tech University. Accessed October 14, 2019. http://hdl.handle.net/2346/73906.

MLA Handbook (7th Edition):

Chalise, Nishant. “Studies of an iron-regulated bacteriocin-like substance in Aeromonas sp.” 2012. Web. 14 Oct 2019.

Vancouver:

Chalise N. Studies of an iron-regulated bacteriocin-like substance in Aeromonas sp. [Internet] [Masters thesis]. Texas Tech University; 2012. [cited 2019 Oct 14]. Available from: http://hdl.handle.net/2346/73906.

Council of Science Editors:

Chalise N. Studies of an iron-regulated bacteriocin-like substance in Aeromonas sp. [Masters Thesis]. Texas Tech University; 2012. Available from: http://hdl.handle.net/2346/73906


Texas Tech University

2. -8220-7851. Lactobacillus species inhibit the growth and biofilm development by wound's bacterial pathogens.

Degree: MS, Microbiology, 2018, Texas Tech University

Chronic wounds are characterized as a wound that fails to heal by three months. Microbial colonization of chronic wounds may be responsible for the delayed healing. The most common wound pathogens include: Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa. Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that is inherently resistant to numerous antibiotics. The multidrug resistance of P. aeruginosa combined with the high cost of producing new antibiotics necessitates the search for other potential therapies to help heal chronic wounds. Lactobacilli, which are the major components in probiotic products, protect the vaginal environment from potentially harmful microorganisms through various mechanisms. Examples of the mechanisms through which lactobacilli keep women healthy include lowering the pH of the environment, secretion of lactic acid, modulation of host cytokines, and production of bacteriocins. The lactobacilli that are most commonly isolated from the vagina are L. gasseri, L. plantarum, and L. crispatus. Based upon known interactions of lactobacilli and other disease-causing bacteria, I hypothesize that certain Lactobacillus strains produce a potential factor(s) that inhibit the growth and/or biofilm development of P. aeruginosa strains. This study aims to provide a potential alternative to treat P. aeruginosa infections through L. gasseri secreted products. Using in-vitro biofilm models, I showed that Lactobacillus gasseri inhibits biofilm development by P. aeruginosa strain PAO1. Zone of inhibition assays showed that 20X-concentrated cell-free supernatant of L. gasseri inhibited the growth of PAO1. I confirmed these results using a quantitative broth assay. I failed to detect colony-forming units (CFU/mL) of PAO1 when the organism was grown in Luria-Bertani broth containing L. gasseri concentrated supernatant. I utilized PAO1/pMP7605, which contains the plasmid pMP7605 that encodes for the red fluorescence protein, to visualize biofilm development. Using confocal microscopy, L. gasseri supernatant was successful in reducing the thickness and growth of PAO1/pMP7605 biofilms as compared to the control. pH alone was not responsible for PAO1 inhibition. While L. gasseri lowered the pH of de Man, Rogosa, and Sharpe (MRS) broth to 3, when MRS broth was adjusted to pH 3 with hydrochloric acid, the lower pH alone had less effect on PAO1 growth as compared to L. gasseri concentrated supernatant. Furthermore, the exact concentration of D- and L-lactic acid that L. gasseri secretes was determined to better understand the ability of L. gasseri to control Pseudomonas biofilm formation. MRS broth was acidified with the same amount of D- and L-lactic acid within the L. gasseri supernatant. The acidified medium reduced PAO1 growth by only 102 CFU/mL confirming that acid alone does not cause the complete inhibition of PAO1 growth. The effect of concentrated supernatant of L. gasseri on the P. aeruginosa strain PA14 and other cystic fibrosis clinical isolates was evaluated and… Advisors/Committee Members: Hamood, Abdul (committee member), Jeter, Randall (committee member), Zak, John (Committee Chair).

Subjects/Keywords: Lactobacilli; Pseudomonas aeruginosa

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

-8220-7851. (2018). Lactobacillus species inhibit the growth and biofilm development by wound's bacterial pathogens. (Masters Thesis). Texas Tech University. Retrieved from http://hdl.handle.net/2346/74419

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Chicago Manual of Style (16th Edition):

-8220-7851. “Lactobacillus species inhibit the growth and biofilm development by wound's bacterial pathogens.” 2018. Masters Thesis, Texas Tech University. Accessed October 14, 2019. http://hdl.handle.net/2346/74419.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

MLA Handbook (7th Edition):

-8220-7851. “Lactobacillus species inhibit the growth and biofilm development by wound's bacterial pathogens.” 2018. Web. 14 Oct 2019.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Vancouver:

-8220-7851. Lactobacillus species inhibit the growth and biofilm development by wound's bacterial pathogens. [Internet] [Masters thesis]. Texas Tech University; 2018. [cited 2019 Oct 14]. Available from: http://hdl.handle.net/2346/74419.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Council of Science Editors:

-8220-7851. Lactobacillus species inhibit the growth and biofilm development by wound's bacterial pathogens. [Masters Thesis]. Texas Tech University; 2018. Available from: http://hdl.handle.net/2346/74419

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

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