Life Sciences Commons^™

Turbidimetric Bioassays: A Solution To Antimicrobial Activity Detection In Asymptomatic Bacteriuria Isolates Against Uropathogenic Escherichia Coli, Ciara Kenneally, Craig P. Murphy, Roy D. Sleator, Eamonn P. Culligan

Department of Biological Sciences Publications

Traditional bacteriocin screening methods often face limitations due to diffusion-related challenges in agar matrices, which can prevent the peptides from reaching their target organism. Turbidimetric techniques offer a solution to these issues, eliminating diffusion-related problems and providing an initial quantification of bacteriocin efficacy in producer organisms. This study involved screening the cell-free supernatant (CFS) from eight uncharacterized asymptomatic bacteriuria (ABU) isolates and Escherichia coli 83972 for antimicrobial activity against clinical uropathogenic E. coli (UPEC) strains using turbidimetric growth methods. ABU isolates exhibiting activity against five or more UPEC strains were further characterized (PUTS 37, PUTS 58, PUTS 59, S-07-4, and …

A Rationally Designed Antimicrobial Peptide From Structural And Functional Insights Of Clostridioides Difficile Translation Initiation Factor 1, Elvira Alanis, Faith Aguilar, Niaz Banaei, Frank B. Dean, Alexa Villarreal, Miguel Alanis, Karen Lozano, James M. Bullard, Yonghong Zhang

School of Integrative Biological and Chemical Sciences Faculty Publications and Presentations

ABSTRACT: A significant increase of hospital-acquired bacterial infections during the COVID-19 pandemic has become an urgent medical problem. Clostridioides difficile is an urgent antibiotic-resistant bacterial pathogen and a leading causative agent of nosocomial infections. The increasing recurrence of C. difficile infection and antibi­otic resistance in C. difficile has led to an unmet need for the discovery of new com­pounds distinctly different from present antimicrobials, while antimicrobial peptides as promising alternatives to conventional antibiotics have attracted growing interest recently. Protein synthesis is an essential metabolic process in all bacteria and a validated antibiotic target. Initiation factor 1 from C. difficile (Cd-IF1) …

Liquid Chromatography Mass Spectrometry Method Development For The Determination Of Β–Defensins In Bovine Milk, Elisha Ogbebor

Masters Theses & Specialist Projects

Bovine mastitis is caused by a wide range of pathogens which results in a substantial economic loss for the dairy cattle livestock industry. β-defensins are a part of the innate immune system and act as the first line of defense against mastitis in bovine. β-defensins (~6- 10kDa) are antimicrobial peptides that contain about 28 to 67 amino acids, the presence of six cysteine residues results in their three disulfide bonds and a β-sheet structure. A few β- defensins have been identified in cows based on the site of occurrence and time of expression in tissue, but not in milk. A …

Antimicrobial Peptide Identification Using Multi-Scale Convolutional Network, Xin Su, Jing Xu, Yanbin Yin, Xiongwen Quan, Han Zhang

Department of Food Science and Technology: Faculty Publications

Background: Antibiotic resistance has become an increasingly serious problem in the past decades. As an alternative choice, antimicrobial peptides (AMPs) have attracted lots of attention. To identify new AMPs, machine learning methods have been commonly used. More recently, some deep learning methods have also been applied to this problem.

Results: In this paper, we designed a deep learning model to identify AMP sequences. We employed the embedding layer and the multi-scale convolutional network in our model. The multi-scale convolutional network, which contains multiple convolutional layers of varying filter lengths, could utilize all latent features captured by the multiple convolutional layers. …

Determining Antimicrobial Activity In Hydrolysates Obtained From Buttermilk Substrates By Trypsin And Pepsin, Deborah Kim, Karen Ramun, Stephanie Carpintero, Suyapa Padillo, Antonio-Jose Trujillo, Rafael Jimenez-Flores

STAR Program Research Presentations

Milk proteins within their structure and sequence, contain peptides that exhibit antithrombotic, immunomodulatory, antimicrobial, antihypertensive, and other bioactivities. These peptides are released as the enzymes cleave milk proteins at certain locations of the amino acid chains. In this research, four different substrates were hydrolyzed with the gastrointestinal enzymes, pepsin and trypsin. The substrates were buttermilk (BM) and whey buttermilk (WBM), which are waste products of butter and cheese production, and supercritical CO₂ fluid (SFE) treated buttermilk (S-BM) and whey buttermilk (S-WBM). SFE acts as a solvent which removes triglycerides from the substrates and changes the overall composition of samples. …

Effect Of Dietary Antibacterial Peptide And Zinc-Methionine On Performance And Serum Biochemical Parameters In Piglets, J. H. Wang, C. C. Wu, J. Feng

Biochemistry Collection

The objective of this study was to evaluate the effect of dietary supplementation of antibacterial peptide and zinc methionine on performance and some serum biochemical parameters of weaned piglets. Rongchang male piglets (28 days of age, initial weight 8.4 ± 0.65 kg) were used. All piglets were randomly allotted to four diets including the control group, the antibacterial peptide (AP) group containing 10 mg antibacterial peptide/kg diet, the zinc methionine (Zn-Met) group with 1 200 zinc methionine/kg diet (equal to 200 mg Zn²⁺/kg diet), the zinc methionine/antibacterial peptide (Zn/AP) group containing 10 mg antibacterial peptide and 1 200 …

A Fourier Transformation Based Method To Mine Peptide Space For Antimicrobial Activity, Vijayaraj Nagarajan, Navodit Kaushik, Beddhu Murali, Chaoyang Zhang, Sanyogita Lakhera, Mohamed O. Elasri, Youping Deng

Faculty Publications

Background

Naturally occurring antimicrobial peptides are currently being explored as potential candidate peptide drugs. Since antimicrobial peptides are part of the innate immune system of every living organism, it is possible to discover new candidate peptides using the available genomic and proteomic data. High throughput computational techniques could also be used to virtually scan the entire peptide space for discovering out new candidate antimicrobial peptides.

Result

We have identified a unique indexing method based on biologically distinct characteristic features of known antimicrobial peptides. Analysis of the entries in the antimicrobial peptide databases, based on our indexing method, using Fourier transformation …

Identification Of A Defensin From The Hemolymph Of The American Dog Tick, Dermacentor Variabilis, Robert Johns, Daniel E. Sonenshine, Wayne L. Hynes

Biological Sciences Faculty Publications

Hemolymph from partially fed virgin Dermacentor variabilis females was collected following Borrelia burgdorferi challenge and assayed for antimicrobial activity against Bacillus subtilis and B. burgdorferi. A small inducible cationic peptide was identified by SDS-PAGE in the hemolymph of these ticks as early as 1h post challenge. Following purification by a three-step procedure involving sequential SepPak elution, reversed phase high performance liquid chromatography (RP-HPLC) and gel electrophoresis, the yield of the active peptide was approximately 0.1% of the total protein in the hemolymph plasma. The molecular weight, 4.2kDa, was determined by MALDI-TOF mass spectrometry. N-terminal sequencing by the Edman degradation …