Medical Microbiology Commons^™

Inactivation Of The Fusobacterium Nucleatum Rnf Complex Reduces Fada-Mediated Amyloid Formation And Tumor Development, Timmie A Britton, Ju Huck Lee, Chungyu Chang, Aadil H Bhat, Yi-Wei Chen, Rusul Mohammed Ali, Chenggang Wu, Asis Das, Hung Ton-That

Faculty, Staff and Student Publications

The Gram-negative anaerobe Fusobacterium nucleatum is an oral oncobacterium that promotes colorectal cancer (CRC) development with the amyloid-forming cell surface adhesin FadA integral to CRC tumorigenesis. We describe here molecular genetic studies uncovering a novel mode of metabolic regulation of FadA-mediated tumor formation by a highly conserved respiratory enzyme known as the Rnf complex. First, we show that genetic disruption of Rnf, via rnfC deletion, significantly reduces the level of fadA transcript, accompanied by a near-complete abolishment of the precursor form of FadA (pFadA), reduced assembly of FadA at the mature cell pole, and severe defects in the osmotic stress-induced …

Enriched Pathways In Gut Microbiome Predict Response To Immune Checkpoint Inhibitor Treatment Across Demographic Regions And Various Cancer Types, Xunhui Cai, Jennifer Y Cho, Lijun Chen, Yufeng Liu, Fenghu Ji, Katia Salgado, Siyi Ge, Dehua Yang, Hui Yu, Jianbo Shao, P Andrew Futreal, Boris Sepesi, Don Gibbons, Yaobing Chen, Guoping Wang, Chao Cheng, Meng Wu, Jianjun Zhang, Ansel Hsiao, Tian Xia

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Understanding the effect of gut microbiota function on immune checkpoint inhibitor (ICI) responses is urgently needed. Here, we integrated 821 fecal metagenomes from 12 datasets to identify differentially abundant genes and construct random forest models to predict ICI response. Gene markers demonstrated excellent predictive performance, with an average area under the curve (AUC) of 0.810. Pathway analyses revealed that quorum sensing (QS), ABC transporters, flagellar assembly, and amino acid biosynthesis pathways were enriched between responders (R) and non-responders (NRs) across 12 datasets. Furthermore,

The Microbiome-Restorative Potential Of Ibezapolstat For The Treatment Of Clostridioides Difficile Infection Is Predicted Through Variant Polc-Type Dna Polymerase Iii In Lachnospiraceae And Oscillospiraceae, Jacob K Mcpherson, Julian G Hurdle, Matthew L Baker, Tahir Hussain, Ashok Kumar, Kevin W Garey

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Ibezapolstat (IBZ), a first-in-class antibiotic targeting the PolC-type DNA polymerase III alpha-subunit (PolC) in low G + C bacteria, is in clinical development for the treatment of Clostridioides difficile infection (CDI). In the phase 2 trials, IBZ had potent activity against C. difficile while sparing or causing regrowth of Lachnospiraceae, Oscillospiraceae, and Erysipelotrichales, common commensal low G + C bacteria. The purpose of this study was to utilize in silico approaches to better interpret the narrower than expected IBZ spectrum of activity. IBZ susceptibility to human commensal microbiota was predicted using genomic analysis and PolC phylogenetic tree construction in relation …

Nomenclature For Human And Animal Fungal Pathogens And Diseases: A Proposal For Standardized Terminology, Sybren De Hoog, Thomas J Walsh, Sarah A Ahmed, Ana Alastruey-Izquierdo, Maiken Cavling Arendrup, Andrew Borman, Sharon Chen, Anuradha Chowdhary, Robert C Colgrove, Oliver A Cornely, David W Denning, Philippe J Dufresne, Laura Filkins, Jean-Pierre Gangneux, Josepa Gené, Andreas H Groll, Jaques Guillot, Gerhard Haase, Catriona Halliday, David L Hawksworth, Roderick Hay, Martin Hoenigl, Vit Hubka, Tomasz Jagielski, Hazal Kandemir, Sarah E Kidd, Julianne V Kus, June Kwon-Chung, Shawn R Lockhart, Jacques F Meis, Leonel Mendoza, Wieland Meyer, M Hong Nguyen, Yinggai Song, Tania C Sorrell, J Benjamin Stielow, Rachel Vilela, Roxana G Vitale, Nancy L Wengenack, P Lewis White, Luis Ostrosky-Zeichner, Sean X Zhang

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Medically important pathogenic fungi invade vertebrate tissue and are considered primary when part of their nature life cycle is associated with an animal host and are usually able to infect immunocompetent hosts. Opportunistic fungal pathogens complete their life cycle in environmental habitats or occur as commensals within or on the vertebrate body, but under certain conditions can thrive upon infecting humans. The extent of host damage in opportunistic infections largely depends on the portal and modality of entry as well as on the host's immune and metabolic status. Diseases caused by primary pathogens and common opportunists, causing the top approximately …

Viability Discrimination Of Bacterial Microbiomes In Home Kitchen Dish Sponges Using Propidium Monoazide Treatment, Christina K Carstens, Joelle K Salazar, Shreela Sharma, Wenyaw Chan, Charles Darkoh

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Dish sponges are known to support the proliferation of human bacterial pathogens, yet they are commonly used by consumers. Exposure to foodborne pathogens via sponge use may lead to illness, a serious concern among susceptible populations. The extent of exposure risks from sponge use has been limited by constraints associated with culture-independent or dependent methods for bacterial community characterization. Therefore, five used dish sponges were characterized to evaluate the presence of viable bacterial foodborne pathogens using the novel application of propidium monoazide (PMA) treatment and targeted 16S rRNA gene amplicon sequencing. Select pathogen viability was confirmed using targeted selective enrichment. …

Phenotypic Diversity Of Type Iii Secretion System Activity In Enteropathogenic Escherichia Coli Clinical Isolates, Carmen A Contreras, Tracy H Hazen, Carmen Guadarrama, Ramón Cervantes-Rivera, Theresa J Ochoa, Pablo Vinuesa, David A Rasko, Jose L Puente

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Introduction. Enteropathogenic Escherichia coli (EPEC) strains pose a significant threat as a leading cause of severe childhood diarrhoea in developing nations. EPEC pathogenicity relies on the type III secretion system (T3SS) encoded by the locus of enterocyte effacement (LEE), facilitating the secretion and translocation of bacterial effector proteins.

Gap Statement. While the regulatory roles of PerC (plasmid-encoded regulator) and GrlA (global regulator of LEE-activator) in ler expression and LEE gene activation are well-documented in the EPEC prototype strain E2348/69, understanding the variability in LEE gene expression control mechanisms among clinical EPEC isolates remains an area requiring further investigation.

Aim. This …

Persistence Of Daptomycin-Resistant And Vancomycin-Resistant Enterococci In Hospitalized Patients With Underlying Malignancies: A 7-Year Follow-Up Study, Lynn El Haddad, Georgios Angelidakis, Yuting Zhai, Layale Yaghi, Cesar A Arias, Samuel A Shelburne, Kwangcheol Casey Jeong, Roy F Chemaly

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Vancomycin-resistant enterococci (VRE) commonly colonize the gut of individuals with hematologic malignancies or undergoing hematopoietic cell transplant (HCT) and may cause bacteremia. In 2012, we identified VRE isolates from patients and patients' rooms and showed transmission networks of highly genetically related daptomycin-resistant (DR)-VRE strains. This is a follow-up study performing whole-genome sequencing (WGS) and phylogenetic analyses on 82 clinical VRE strains isolated from stools and blood cultures of patients with leukemia and HCT between 2015 and 2019. Here, we observed transmission of highly genetically related strains between rooms on the same or on different floors, including a DR-VRE strain identified …

Women In Stem Becoming Independent: Our Shared Motivation And Enthusiasm Are Our Driving Force, Liudmila Andreeva, Lidia Bosurgi, Shu Zhen Chong, Coco Chu, Yejing Ge, Esther Hoste, Kellie A Jurado, Jette Lengefeld, Archita Mishra, Stefanie Wculek, Arabella Young

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This year at JEM, we are highlighting women in science by sharing their stories and amplifying their voices. In this Viewpoint, we hear from a cross section of women, across multiple research fields, discussing their science and the process of setting up a lab as an independent researcher.

Vertebrate And Invertebrate Animal Infection Models Of Candida Auris Pathogenicity, Melissa Martinez, Danielle A Garsin, Michael C Lorenz

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Candida auris is an emerging fungal pathogen with several concerning qualities. First recognized in 2009, it has arisen in multiple geographically distinct genomic clades nearly simultaneously. C. auris strains are typically multidrug resistant and colonize the skin much better than most other pathogenic fungi; it also persists on abiotic surfaces, enabling outbreaks due to transmission in health care facilities. All these suggest a biology substantially different from the 'model' fungal pathogen, Candida albicans and support intensive investigation of C. auris biology directly. To uncover novel virulence mechanisms in this species requires the development of appropriate animal infection models. Various studies …

The Significant Role Of Amino Acid Metabolic Reprogramming In Cancer, Xiaohong Liu, Bo Ren, Jie Ren, Minzhi Gu, Lei You, Yupei Zhao

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Amino acid metabolism plays a pivotal role in tumor microenvironment, influencing various aspects of cancer progression. The metabolic reprogramming of amino acids in tumor cells is intricately linked to protein synthesis, nucleotide synthesis, modulation of signaling pathways, regulation of tumor cell metabolism, maintenance of oxidative stress homeostasis, and epigenetic modifications. Furthermore, the dysregulation of amino acid metabolism also impacts tumor microenvironment and tumor immunity. Amino acids can act as signaling molecules that modulate immune cell function and immune tolerance within the tumor microenvironment, reshaping the anti-tumor immune response and promoting immune evasion by cancer cells. Moreover, amino acid metabolism can …

Intratumoral Microbiome Of Adenoid Cystic Carcinomas And Comparison With Other Head And Neck Cancers, Tatiana V Karpinets, Yoshitsugu Mitani, Chia-Chi Chang, Xiaogang Wu, Xingzhi Song, Ivonne I Flores, Lauren K Mcdaniel, Yasmine M Hoballah, Fabiana J Veguilla, Renata Ferrarotto, Lauren E Colbert, Nadim J Ajami, Robert R Jenq, Jianhua Zhang, Andrew P Futreal, Adel K El-Naggar

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Adenoid cystic carcinoma (ACC) is a rare, usually slow-growing yet aggressive head and neck malignancy. Despite its clinical significance, our understanding of the cellular evolution and microenvironment in ACC remains limited. We investigated the intratumoral microbiomes of 50 ACC tumor tissues and 33 adjacent normal tissues using 16S rRNA gene sequencing. This allowed us to characterize the bacterial communities within the ACC and explore potential associations between the bacterial community structure, patient clinical characteristics, and tumor molecular features obtained through RNA sequencing. The bacterial composition in the ACC was significantly different from that in adjacent normal salivary tissue, and the …

Baseline Data Collections Of Lipopolysaccharide Content In 414 Herbal Extracts And Its Role In Innate Immune Activation, Vindy Tjendana Tjhin, Masataka Oda, Masashi Yamashita, Tomoko Iwaki, Yasuko Fujita, Koji Wakame, Hiroyuki Inagawa, Gen-Ichiro Soma

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Some herbal extracts contain relatively high amounts of lipopolysaccharide (LPS). Because orally administered LPS activates innate immunity without inducing inflammation, it plays a role as an active ingredient in herbal extracts. However, the LPS content in herbal extracts remains extensively unevaluated. This study aimed to create a database of LPS content in herbal extracts; therefore, the LPS content of 414 herbal extracts was measured and the macrophage activation potential was evaluated. The LPS content of these hot water extracts was determined using the kinetic-turbidimetric method. The LPS concentration ranged from a few ng/g to hundreds of μg/g (Standard Escherichia coli …

In-Silico Analysis Of Tmem2 As A Pancreatic Adenocarcinoma And Cancer-Associated Fibroblast Biomarker, And Functional Characterization Of Nsc777201, For Targeted Drug Development, Prateeti Srivastava, Vijesh Kumar Yadav, Tzu-Hao Chang, Emily Chia-Yu Su, Bashir Lawal, Alexander Th Wu, Hsu-Shan Huang

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Pancreatic adenocarcinoma (PAAD), known as one of the deadliest cancers, is characterized by a complex tumor microenvironment, primarily comprised of cancer-associated fibroblasts (CAFs) in the extracellular matrix. These CAFs significantly alter the matrix by interacting with hyaluronic acid (HA) and the enzyme hyaluronidase, which degrades HA - an essential process for cancer progression and spread. Despite the critical role of this interaction, the specific functions of CAFs and hyaluronidase in PAAD development are not fully understood. Our study investigates this interaction and assesses NSC777201, a new anti-cancer compound targeting hyaluronidase. This research utilized computational methods to analyze gene expression data …

Identification And Characterization Of Cannabichromene's Major Metabolite Following Incubation With Human Liver Microsomes, Alexandra M Ward, Touraj Shokati, Jost Klawitter, Jelena Klawitter, Vu Nguyen, Laura Kozell, Atheir I Abbas, David Jones, Uwe Christians

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Cannabichromene (CBC) is a minor cannabinoid within the array of over 120 cannabinoids identified in the Cannabis sativa plant. While CBC does not comprise a significant portion of whole plant material, it is available to the public in a purified and highly concentrated form. As minor cannabinoids become more popular due to their potential therapeutic properties, it becomes crucial to elucidate their metabolism in humans. Therefore, the goal of this was study to identify the major CBC phase I-oxidized metabolite generated in vitro following incubation with human liver microsomes. The novel metabolite structure was identified as 2′-hydroxycannabicitran using gas chromatography–mass …

Mycoplasmoides Genitalium Nucleic Acid Semi-Quantitation And Molecular Macrolide Resistance Detection Via Automated Assays: Gender And Specimen Source Considerations, Erik Munson, Josephine Moore, Trinity Krueger, Amanda Zapp, Stephen C Lavey, Kimber L Munson, Irene A Stafford, Brian Mustanski

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A laboratory-developed test (LDT) using analyte-specific reagents has been optimized on a commercial platform to detect macrolide resistance-associated mutations (MRM) in 23S rRNA from Mycoplasmoides genitalium from primary clinical specimens. In this study, MRM-LDT was applied to a multi-specimen source study set. One thousand four hundred ninety-five primary specimens testing positive for M. genitalium by commercial transcription-mediated amplification (TMA) were initially titered by the TMA assay using serial 10-fold dilutions to semi-quantitate target nucleic acid burden. Primary specimens were then processed for MRM detection using the MRM-LDT. Findings were stratified by gender and specimen source. The mean log10 target nucleic …

Quantitative Proteomic Analysis Reveals Unique Hsp90 Cycle-Dependent Client Interactions, Erick I Rios, Davi Gonçalves, Kevin A Morano, Jill L Johnson

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Hsp90 is an abundant and essential molecular chaperone that mediates the folding and activation of client proteins in a nucleotide-dependent cycle. Hsp90 inhibition directly or indirectly impacts the function of 10-15% of all proteins due to degradation of client proteins or indirect downstream effects. Due to its role in chaperoning oncogenic proteins, Hsp90 is an important drug target. However, compounds that occupy the ATP-binding pocket and broadly inhibit function have not achieved widespread use due to negative effects. More selective inhibitors are needed; however, it is unclear how to achieve selective inhibition. We conducted a quantitative proteomic analysis of soluble …

The Kat Module Of The Saga Complex Maintains The Oncogenic Gene Expression Program In Mycn- Amplified Neuroblastoma, Clare F Malone, Nathaniel W Mabe, Alexandra B Forman, Gabriela Alexe, Kathleen L Engel, Ying-Jiun C Chen, Melinda Soeung, Silvi Salhotra, Allen Basanthakumar, Bin Liu, Sharon Y R Dent, Kimberly Stegmaier

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Pediatric cancers are frequently driven by genomic alterations that result in aberrant transcription factor activity. Here, we used functional genomic screens to identify multiple genes within the transcriptional coactivator Spt-Ada-Gcn5-acetyltransferase (SAGA) complex as selective dependencies for MYCN-amplified neuroblastoma, a disease of dysregulated development driven by an aberrant oncogenic transcriptional program. We characterized the DNA recruitment sites of the SAGA complex in neuroblastoma and the consequences of loss of SAGA complex lysine acetyltransferase (KAT) activity on histone acetylation and gene expression. We demonstrate that loss of SAGA complex KAT activity is associated with reduced MYCN binding on chromatin, suppression of …

Evaluation Of Fusobacterium Nucleatum Enoyl-Acp Reductase (Fabk) As A Narrow-Spectrum Drug Target, Jacob T Rutherford, Kristiana Avad, Chetna Dureja, Krissada Norseeda, Bibek Gc, Chenggang Wu, Dianqing Sun, Kirk E Hevener, Julian G Hurdle

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Fusobacterium nucleatum, a pathobiont inhabiting the oral cavity, contributes to opportunistic diseases, such as periodontal diseases and gastrointestinal cancers, which involve microbiota imbalance. Broad-spectrum antimicrobial agents, while effective against F. nucleatum infections, can exacerbate dysbiosis. This necessitates the discovery of more targeted narrow-spectrum antimicrobial agents. We therefore investigated the potential for the fusobacterial enoyl-ACP reductase II (ENR II) isoenzyme FnFabK (C4N14_ 04250) as a narrow-spectrum drug target. ENRs catalyze the rate-limiting step in the bacterial fatty acid synthesis pathway. Bioinformatics revealed that of the four distinct bacterial ENR isoforms, F. nucleatum specifically encodes FnFabK. Genetic studies revealed …

Optimization Of The Antifungal Properties Of The Bacterial Peptide Entv By Variant Analysis, Shantanu Guha, Shane A Cristy, Giuseppe Buda De Cesare, Melissa R Cruz, Michael C Lorenz, Danielle A Garsin

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Fungal resistance to commonly used medicines is a growing public health threat, and there is a dire need to develop new classes of antifungals. We previously described a peptide produced by Enterococcus faecalis, EntV, that restricts Candida albicans to a benign form rather than having direct fungicidal activity. Moreover, we showed that one 12-amino acid (aa) alpha helix of this peptide retained full activity, with partial activity down to the 10aa alpha helix. Using these peptides as a starting point, the current investigation sought to identify the critical features necessary for antifungal activity and to screen for new variants …

Autologous Bone Marrow Mononuclear Cells To Treat Severe Traumatic Brain Injury In Children, Charles S Cox, David M Notrica, Jenifer Juranek, Jeffrey H Miller, Fabio Triolo, Steven Kosmach, Sean I Savitz, P David Adelson, Claudia Pedroza, Scott D Olson, Michael C Scott, Akshita Kumar, Benjamin M Aertker, Henry W Caplan, Margaret L Jackson, Brijesh S Gill, Robert A Hetz, Michael S Lavoie, Linda Ewing-Cobbs

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Autologous bone marrow mononuclear cells (BMMNCs) infused after severe traumatic brain injury have shown promise for treating the injury. We evaluated their impact in children, particularly their hypothesized ability to preserve the blood–brain barrier and diminish neuroinflammation, leading to structural CNS preservation with improved outcomes.

We performed a randomized, double-blind, placebo-sham-controlled Bayesian dose-escalation clinical trial at two children's hospitals in Houston, TX and Phoenix, AZ, USA (NCT01851083). Patients 5–17 years of age with severe traumatic brain injury (Glasgow Coma Scale score ≤ 8) were randomized to BMMNC or placebo (3:2). Bone marrow harvest, cell isolation and infusion were …

Study On A Strong Polymer Gel By The Addition Of Micron Graphite Oxide Powder And Its Plugging Of Fracture, Bin Shi, Guangming Zhang, Lei Zhang, Chengjun Wang, Zhonghui Li, Fangping Chen

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It is difficult to plug the fracture water channeling of a fractured low-permeability reservoir during water flooding by using the conventional acrylamide polymer gel due to its weak mechanical properties. For this problem, micron graphite powder is added to enhance the comprehensive properties of the acrylamide polymer gel, which can improve the plugging effect of fracture water channeling. The chemical principle of this process is that the hydroxyl and carboxyl groups of the layered micron graphite powder can undergo physicochemical interactions with the amide groups of the polyacrylamide molecule chain. As a rigid structure, the graphite powder can support the …

Quorum-Sensing Agr System Of Staphylococcus Aureus Primes Gene Expression For Protection From Lethal Oxidative Stress, Magdalena Podkowik, Andrew I Perault, Gregory Putzel, Andrew Pountain, Jisun Kim, Ashley L Dumont, Erin E Zwack, Robert J Ulrich, Theodora K Karagounis, Chunyi Zhou, Andreas F Haag, Julia Shenderovich, Gregory A Wasserman, Junbeom Kwon, John Chen, Anthony R Richardson, Jeffrey N Weiser, Carla R Nowosad, Desmond S Lun, Dane Parker, Alejandro Pironti, Xilin Zhao, Karl Drlica, Itai Yanai, Victor J Torres, Bo Shopsin

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The agr quorum-sensing system links Staphylococcus aureus metabolism to virulence, in part by increasing bacterial survival during exposure to lethal concentrations of H2O2, a crucial host defense against S. aureus. We now report that protection by agr surprisingly extends beyond post-exponential growth to the exit from stationary phase when the agr system is no longer turned on. Thus, agr can be considered a constitutive protective factor. Deletion of agr resulted in decreased ATP levels and growth, despite increased rates of respiration or fermentation at appropriate oxygen tensions, suggesting that Δagr cells undergo a shift towards a hyperactive metabolic …

Eye Infection Risks From Pseudomonas Aeruginosa Via Hand Soap And Eye Drops, Anna Gitter, Kristina D Mena, Karla S Mendez, Fuqing Wu, Charles P Gerba

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Eye infections from bacterial contamination of bulk-refillable liquid soap dispensers and artificial tear eye drops continue to occur, resulting in adverse health outcomes that include impaired vision or eye enucleation. Pseudomonas aeruginosa (P. aeruginosa), a common cause of eye infections, can grow in eye drop containers and refillable soap dispensers to high numbers. To assess the risk of eye infection, a quantitative microbial risk assessment for P. aeruginosa was conducted to predict the probability of an eye infection for two potential exposure scenarios: (i) individuals using bacteria-contaminated eye drops and (ii) contact lens wearers washing their hands with …

Syntaxin 3 Is Haplosufficient For Long-Term Photoreceptor Survival In The Mouse Retina, Tahira Jabeen, Muhammad Shahid Khan, Sana Javaid, Waqar Azeem, Rabia Ayoub, Martin Motola

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Here, synthesis and thorough characterization of β-NaFeO2 nanoparticles utilizing a co-precipitation technique is presented. XRD analysis confirmed a hexagonal-phase structure of β-NaFeO2. SEM revealed well-dispersed spherical nanoparticles with an average diameter of 45 nm. The FTIR spectrum analysis revealed weak adsorption bands at 1054 cm-1 suggested metal-metal bond stretching (Fe-Na). UV-Visible spectroscopy indicates a 4.4 eV optical band gap. Colloidal stability of β-NaFeO2 was evidenced via Zeta potential (-28.5 mV) and Dynamic Light Scattering (DLS) measurements. BET analysis reveals a substantial 343.27 m2 g-1 surface area with mesoporous characteristics. Antioxidant analysis indicates efficacy comparable to standard antioxidants, while concentration-dependent antibacterial …

Genomes Of Bacteroides Ovatus, B Cellulosilyticus, B Uniformis, Phocaeicola Vulgatus, And P Dorei Isolated From Gut Cavernous Fistulous Tract Micropathologies In Crohn’S Disease, Vaidhvi Singh, Gail West, Claudio Fiocchi, Fabio Cominelli, Caryn E Good, Michael R Jacobs, Alexander Rodriguez-Palacios

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Surgically removed bowels from Crohn's disease patients exhibit a novel form of micropathologies known as cavernous fistulous tract microlesions (CavFT), resembling fissures. We announce the genomes/plasmids and antimicrobial resistance genes of six CavFT bacterial isolates representing the Bacteroidota genera Bacteroides and Phocaeicola. Plasmids were identified in Bacteroides cellulosilyticus and Phocaeicola vulgatus.

Identification Of Novel F2-Isoprostane Metabolites By Specific Udp-Glucuronosyltransferases, Ginger L Milne, Marina S Nogueira, Benlian Gao, Stephanie C Sanchez, Warda Amin, Sarah Thomas, Camille Oger, Jean-Marie Galano, Harvey J Murff, Gong Yang, Thierry Durand

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UDP-glucuronosyltransferases (UGTs) catalyze the conjugation of glucuronic acid with endogenous and exogenous lipophilic small molecules to facilitate their inactivation and excretion from the body. This represents approximately 35 % of all phase II metabolic transformations. Fatty acids and their oxidized eicosanoid derivatives can be metabolized by UGTs. F2-isoprostanes (F2-IsoPs) are eicosanoids formed from the free radical oxidation of arachidonic acid. These molecules are potent vasoconstrictors and are widely used as biomarkers of endogenous oxidative damage. An increasing body of evidence demonstrates the efficacy of measuring the β-oxidation metabolites of F2-IsoPs rather than the unmetabolized F2-IsoPs to quantify oxidative damage in …

Rfx Transcription Factor In The Human-Associated Yeast Candida Albicans Regulates Adhesion To Oral Epithelium, Diana L Rodríguez, Elena Lindemann-Perez, J Christian Perez

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Adhesion to mucosal surfaces is a critical step in many bacterial and fungal infections. Here, using a mouse model of oral infection by the human fungal pathobiont Candida albicans, we report the identification of a novel regulator of C. albicans adhesion to the oral mucosa. The regulator is a member of the regulatory factor X (RFX) family of transcription factors, which control cellular processes ranging from genome integrity in model yeasts to tissue differentiation in vertebrates. Mice infected with the C. albicans rfx1 deletion mutant displayed increased fungal burden in tongues compared to animals infected with the reference strain. High-resolution …

Cytoplasmic Redox Imbalance In The Thioredoxin System Activates Hsf1 And Results In Hyperaccumulation Of The Sequestrase Hsp42 With Misfolded Proteins, Davi Goncalves, Duong Long Duy, Sara Peffer, Kevin A Morano

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Cells employ multiple systems to maintain homeostasis when experiencing environmental stress. For example, the folding of nascent polypeptides is exquisitely sensitive to proteotoxic stressors including heat, pH, and oxidative stress, and is safeguarded by a network of protein chaperones that concentrate potentially toxic misfolded proteins into transient assemblies to promote folding or degradation. The redox environment itself is buffered by both cytosolic and organellar thioredoxin and glutathione pathways. How these systems are linked is poorly understood. Here, we determine that specific disruption of the cytosolic thioredoxin system resulted in constitutive activation of the heat shock response in Saccharomyces cerevisiae and …

Chimeric Systems Composed Of Swapped Tra Subunits Between Distantly-Related F Plasmids Reveal Striking Plasticity Among Type Iv Secretion Machines, Kouhei Kishida, Yang Grace Li, Natsumi Ogawa-Kishida, Pratick Khara, Abu Amar M Al Mamun, Rachel E Bosserman, Peter J Christie

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Bacterial type IV secretion systems (T4SSs) are a versatile family of macromolecular translocators, collectively able to recruit diverse DNA and protein substrates and deliver them to a wide range of cell types. Presently, there is little understanding of how T4SSs recognize substrate repertoires and form productive contacts with specific target cells. Although T4SSs are composed of a number of conserved subunits and adopt certain conserved structural features, they also display considerable compositional and structural diversity. Here, we explored the structural bases underlying the functional versatility of T4SSs through systematic deletion and subunit swapping between two conjugation systems encoded by the …

Structural Basis Of A Transcription Pre-Initiation Complex On A Divergent Promoter, Tiago R D Costa, Jonasz B Patkowski, Kévin Macé, Peter J Christie, Gabriel Waksman

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Considerable progress has been made in recent years in the structural and molecular biology of type IV secretion systems in Gram-negative bacteria. The latest advances have substantially improved our understanding of the mechanisms underlying the recruitment and delivery of DNA and protein substrates to the extracellular environment or target cells. In this Review, we aim to summarize these exciting structural and molecular biology findings and to discuss their functional implications for substrate recognition, recruitment and translocation, as well as the biogenesis of extracellular pili. We also describe adaptations necessary for deploying a breadth of processes, such as bacterial survival, host–pathogen …