Expanding Our Grasp Of Two-Component Signaling In Clostridioides Difficile, Orlando Berumen Alvarez, Erin B. Purcell

Chemistry & Biochemistry Faculty Publications

The intestinal pathogen Clostridioides difficile encodes roughly 50 TCS, but very few have been characterized in terms of their activating signals or their regulatory roles. A. G. Pannullo, B. R. Zbylicki, and C. D. Ellermeier (J Bacteriol 205:e00164-23, 2023, https://doi.org/10.1128/jb.00164-23) have identified both for the novel C. difficile TCD DraRS. DraRS responds to antibiotics that target lipid-II molecules in the bacterial cell envelope, and regulates the production of a novel glycolipid necessary for bacitracin and daptomycin resistance in C. difficile.

Antibacterial Activity, Structure-Activity Relationships, And Scale-Up Reaction Of 1,3,4-Oxadiazoles, Olivia Marie Smith

Undergraduate Honors Thesis Projects

Oxadiazoles are compounds in the field of organic chemistry that have been gathering interest in the medicinal chemistry and microbiology communities for their biological properties, which range from anti-inflammatory agents, to chemotherapy drugs, to antibiotics. The synthesis of oxadiazoles can be difficult due to the expensive and complex nature of the techniques used as well as the volatile reagents and elevated temperatures that are often required in organic synthesis. The Grote lab has recently developed a new method for the synthesis of 1,3,4-oxadiazoles under mild conditions. The goals of this thesis were thus twofold: to develop a viable scale-up procedure …

Influence Of Conformational Restriction On The Antibacterial Activity And Ribosomal Selectivity Of Aminoglycoside Antibiotics, Michael Gabriel Pirrone

Wayne State University Dissertations

The ever-increasing threat posed by multidrug-resistant infectious bacteria necessitates

the development of novel antibiotics. Aminoglycoside antibiotics are growing in interest due to

their broad spectrum of activity, lack of known drug related allergies, low manufacturing cost,

and their well-studied mechanism of action. The simplification of rational drug design due to the

well-studied mechanism of action is the key to overcoming the issues presented by these drugs,

namely ototoxicity and nephrotoxicity.

A study of the effect of the conformation of the aminoglycoside ring I side chain is

described wherein it was discovered that an increase in a particular conformation augments the …

Part 1: Design, Synthesis, And Evaluation Of Novel Gram-Positive Antibiotics Part 2: Synthesis Of Dihydrobenzofurans Via A New Transition Metal Catalyzed Reaction Part 3: Design, Synthesis, And Evaluation Of Bz/Gabaa Α6 Positive Allosteric Modulators, Christopher Michael Witzigmann

Theses and Dissertations

Part 1. Lead compound SK-03-92 represents a new scaffold for antibiotic drug discovery. Development of a new process for the synthesis of analogs has led to the development of a number of new ligands with even more potent activity against gram-positive bacteria, including drug-resistant strains of S. aureus. Compounds 36 and 38 represent some of the most potent analogs developed thus far, and preliminary results indicate that they are also not cytotoxic. Research into a Heck-mediated transition metal catalyzed pathway towards electron-rich stilbenoid analogs has greatly expanded the scope of future SAR studies. This development has led to 14 new …

Synthesis Of Apramycin And Paromomycin Derivatives As Potential Next Generation Aminoglycoside Antibiotics And Chemistry Of Isothiocyanato Sialyl Donors, Appi Reddy Mandhapati

Wayne State University Dissertations

AGAs are clinically important antibacterials for human therapy and have long been used as highly potent antibiotics for treating several bacterial infections. The fidelity of protein synthesis is affected by AGAs in the course of binding to specific sites of the bacterial rRNA. The clinical use of AGAs and their applications as therapeutics is restricted by toxicity (irreversible ototoxicity and reversible nephrotoxicity) and by the resistance of pathogens. The objective of this research was the development of proficient AGAs that are less toxic (i.e., more selective) and that evade resistance. The first three chapters of this thesis are aimed towards …

Adsorption Of Antibiotics By Vermiculite, Mosa J. Ferdous

Dissertations and Theses

The occurrence of residual antibiotics in the environment has been a worldwide issue and warrants the development of inexpensive yet effective methods for antibiotics removal from contaminated water. In this thesis work, the adsorption of four antibiotics, namely chlorotetracycline (CTC), oxytetracycline (OTC), ofloxacin (OFL), and enrofloxacin (ENR), onto natural vermiculite has been studied using batch (static) and column (dynamic) adsorption techniques. The Langmuir and Freundlich isotherm models were initially used to explain the adsorption processes. The separation factor (RL) values derived from the Langmuir model and the 1/n values derived from Freundlich model in the present investigation were less than …

Chemoenzymatic Synthesis Of An Analogue Of The Potent Antifungal Mycosubtilin, Mayank Srivastava

Master's Theses and Doctoral Dissertations

Mycosubtilin is a naturally occurring antifungal obtained from Bacillus subtilis that also displays limited antibiotic activity. Structurally, mycosubtilin is a macrocycliclipoheptapeptide of sequence Asn-Tyr-Asn-Gln-Pro-Ser-Asn, with the N-terminal Asn joined by a β-amino fatty acid. Besides the antifungal and antibiotic activities,these molecules are also hemolytic in nature. Hence, the purpose of this study is to synthesize a potent antifungal analogue of mycosubtilin, with a modified β-amino fatty acid, devoid of any hemolytic activity. A chemoenzymatic approach was used to synthesize the cyclic peptide, which involved the synthesis of the linear peptide chain of desired amino acid sequence, thiophenylderivatization of the peptide …

Anti-Germinants As A New Strategy To Prevent Clostridium Difficile Infections, Amber Janece Howerton

UNLV Theses, Dissertations, Professional Papers, and Capstones

Clostridium difficileinfections (CDI) have emerged as a leading cause of hospital-associated complications. CDI is the major cause of antibiotic-related cases of diarrhea and nearly all cases of pseudomembranous colitis. The infective form of C. difficileis the spore, a dormant and hardy structure that forms under stress. Germination of C. difficile spores into toxin producing bacteria in the GI tract of susceptible patients is the first step in CDI establishment. Patient susceptibility occurs with a disruption of the natural gut microbiota by broad-spectrum antibiotics. Antibiotic treatments usually resolve CDI but refractory cases are on the rise. Of great concern is the …

Library Synthesis Of Anticancer And Antibacterial Agents Via Azide Chemistry, Jianjun Zhang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Various anticancer and antibacterial agents have been synthesized via azide chemistry by taking advantage of carbohydrate. Starting from the synthesis of 14 glycosyl azides, a library of carbohydrate-oxazolidinone conjugates and a library of carbohydrate-cyclopamine conjugates with biological interests were synthesized based on a highly efficient "click reaction" assisted by sonication. Some of the conjugates have improved solubility and enhanced anticancer activity.

A library of neomycin B derivatives with various modifications at the 5" position has been synthesized. Two leads exhibit prominent activity against both methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). Antibacterial activities were measured when combined with other …