BOARD # 392: LSAMP: A roadmap for institution collaboration during Louis Stokes Alliances for Minority Partnerships (LSAMP) program development

2025-08-21

Unseen Drivers of Antimicrobial Resistance: The Role of Industrial Agriculture and Climate Change in This Global Health Crisis

Challenges · 2025-04-21 · 4 citations

Antimicrobial resistance (AMR) is an urgent global health threat with many anthropogenic drivers outside of healthcare. The impacts of modern agriculture on human health are manifold, from the food systems and dietary patterns they support to the less apparent effects of environmental stresses and biodiversity loss in ecosystems. Intensive practices, such as chemical fertilizers, pesticides, and herbicides, induce abiotic stresses that deplete biodiversity and drive AMR in soil and aquatic microbiomes. The overuse of antibiotics in livestock production is another major driver of AMR. Changes in weather patterns due to climate change have the potential to exacerbate these issues as warmer and wetter weather increases the potential for bacterial infection. While practices exist to address healthcare-associated drivers, the impact of agriculture and environmental destruction are not widely appreciated in healthcare and biomedical sciences. It is imperative that healthcare professionals and public health experts understand these connections to properly address the emergent issue of AMR. This review aims to summarize the current data on important agricultural and environmental drivers of AMR for educational purposes, to fill gaps in knowledge, and to improve current practices and stimulate further research.

Identification of novel toxins associated with the extracellular contractile injection system using machine learning

Molecular Systems Biology · 2024-07-28 · 7 citations

Secretion systems play a crucial role in microbe-microbe or host-microbe interactions. Among these systems, the extracellular contractile injection system (eCIS) is a unique bacterial and archaeal extracellular secretion system that injects protein toxins into target organisms. However, the specific proteins that eCISs inject into target cells and their functions remain largely unknown. Here, we developed a machine learning classifier to identify eCIS-associated toxins (EATs). The classifier combines genetic and biochemical features to identify EATs. We also developed a score for the eCIS N-terminal signal peptide to predict EAT loading. Using the classifier we classified 2,194 genes from 950 genomes as putative EATs. We validated four new EATs, EAT14-17, showing toxicity in bacterial and eukaryotic cells, and identified residues of their respective active sites that are critical for toxicity. Finally, we show that EAT14 inhibits mitogenic signaling in human cells. Our study provides insights into the diversity and functions of EATs and demonstrates machine learning capability of identifying novel toxins. The toxins can be employed in various applications dependently or independently of eCIS.

Hierarchical determinants in cytotoxic necrotizing factor (CNF) toxins driving Rho G-protein deamidation versus transglutamination

mBio · 2024-06-26 · 1 citations

ABSTRACT The cytotoxic necrotizing factor (CNF) family of AB-type bacterial protein toxins catalyze two types of modification on their Rho GTPase substrates: deamidation and transglutamination. It has been established that E. coli CNF1 and its close homolog proteins catalyze primarily deamidation and Bordetella dermonecrotic toxin (DNT) catalyzes primarily transglutamination. The rapidly expanding microbial genome sequencing data have revealed that there are at least 13 full-length variants of CNF1 homologs. CNFx from E. coli strain GN02091 is the most distant from all other members of the CNF family with 50%–55% sequence identity at the protein level and 0.45–0.52 nucleotide substitutions per site at the DNA level. CNFx modifies RhoA, Rac1, and Cdc42, and like CNF1, activates downstream SRE-dependent mitogenic signaling pathways in human HEK293T cells, but at a 1,000-fold higher EC 50 value. Unlike other previously characterized CNF toxins, CNFx modifies Rho proteins primarily through transglutamination, as evidenced by gel-shift assay and confirmed by MALDI mass spectral analysis, when coexpressed with Rho-protein substrates in E. coli BL21 cells or through direct treatment of HEK293T cells. A comparison of CNF1 and CNFx sequences identified two critical active-site residues corresponding to positions 832 and 862 in CNF1. Reciprocal site-specific mutations at these residues in each toxin revealed hierarchical rules that define the preference for deamidase versus a transglutaminase activity in CNFs. An additional unique Cys residue at the C-terminus of CNFx was also discovered to be critical for retarding cargo delivery. IMPORTANCE Cytotoxic necrotizing factor (CNF) toxins not only play important virulence roles in pathogenic E. coli and other bacterial pathogens, but CNF-like genes have also been found in an expanding number of genomes from clinical isolates. Harnessing the power of evolutionary relationships among the CNF toxins enabled the deciphering of the hierarchical active-site determinants that define whether they modify their Rho GTPase substrates through deamidation or transglutamination. With our finding that a distant CNF variant (CNFx) unlike other known CNFs predominantly transglutaminates its Rho GTPase substrates, the paradigm of “CNFs deamidate and DNTs transglutaminate” could finally be attributed to two critical amino acid residues within the active site other than the previously identified catalytic Cys-His dyad residues. The significance of our approach and research findings is that they can be applied to deciphering enzyme reaction determinants and substrate specificities for other bacterial proteins in the development of precision therapeutic strategies.

Vascular Endothelial Growth Factor A Contributes to Increased Mammalian Respiratory Epithelial Permeability Induced by Pasteurella multocida Infection

Microbiology Spectrum · 2023 · 25 citations

• Biology
• Immunology
• Microbiology

causing infections in both animals and humans.

Perspective Chapter: Natural Adjuvants for Mucosal Vaccines – The Promise of Tomatine as an Inherent Adjuvant in Tomatoes

Pharmaceutical science. · 2023-11-22 · 2 citations

Certain natural immunostimulatory compounds inherent to plants, animals, and microorganisms, in both terrestrial and aquatic ecosystems, have been reported to enhance the immunogenicity of vaccines by conferring an adjuvant effect and/or possessing potent immunomodulatory properties acting as immunogens themselves. In this chapter, we summarize the current state of vaccine adjuvant development and application, encompassing a range of immunomodulatory compounds that improve protective immune responses and enhance vaccine efficacy. We place special focus on the effectiveness of tomatine, inherent to tomatoes, as a natural immunostimulant. We discuss the adjuvant- and immunomodulatory-properties of tomatine and its advantages in plant-based vaccine production, cost-effectiveness, development, safety profiles, and applications compared to other adjuvants and vaccine delivery systems. This chapter provides a futuristic overview and insights into the promise of tomatine for the development of safer, easily-scalable, sustainable, and more efficient vaccines.

Perspective Chapter: The Most Natural Possible Vaccine Administered in the Most Natural Possible Way - Noninvasive over Injectable Vaccine Delivery Routes

IntechOpen eBooks · 2023-11-14 · 1 citations

This chapter provides perspective on the routes of vaccine administration, comparing invasive and noninvasive delivery methods. We begin with an analysis of the most frequently used routes of administration: invasive, such as traditional needle-based injections (intramuscular and subcutaneous) and noninvasive, including oral and intranasal routes. We discuss recent advancements, for example, aerosols and jet injectors, as well as other novel administration methods for immunization such as improved mucosally-administered vaccines. Finally, we provide an update on how different delivery methods can impact consumer (vaccine recipients) compliance rates and vaccine availability (e.g., cold chain logistics in areas of the world with infrastructure limitations) from the perspectives of both the vaccine provider and the vaccine recipient.

Vascular endothelial growth factor A contributes to the increasing of mammalian respiratory epithelial permeability induced by <i>Pasteurella multocida</i> infection

bioRxiv (Cold Spring Harbor Laboratory) · 2022-10-30

Abstract Infections with Pasteurella multocida can cause significant zoonotic respiratory problems in both humans and animals. In vivo tests in mouse infection models were used to investigate the mechanisms of respiratory epithelial barrier dysfunction during respiratory bacterial infection with these pathogens. Results revealed that P. multocida infection significantly increased epithelial permeability and increased expression of vascular endothelial growth factor A (VEGFA) and endothelial nitric oxide synthase (eNOS) in murine tracheae and lungs. In murine lung epithelial cell (MLE-12) models, P. multocida infection decreased the expression of tight junctions (ZO-1) and adherens junctions (β-catenin, E-cadherin), but induced the activation of the hypoxia-inducible factor-1α (HIF-1α) and VEGFA signaling. When expression of HIF-1α is suppressed, the induction of VEGFA and ZO-1expression by P. multocida infection is decreased. We also found that intervention of HIF-1α and VEGFA signaling affected infection outcomes caused by respiratory bacteria in mouse models. Most importantly, we demonstrated that P. multocida infection increased permeability of human respiratory epithelial cells and this process was associated with the activation of the HIF-1α and VEGFA signaling and likely contributes to the pathogenesis of P. multocida in humans. Importance Mammalian respiratory epithelium forms the first line of defense against infections with Pasteurella multocida , an important zoonotic respiratory pathogen. In this study, we found P. multocida infection increased respiratory epithelial permeability and promoted the induction of the hypoxia-HIF-1α-VEGFA axis in both mouse and murine cell models. Similar findings were also demonstrated in human respiratory epithelial cells. The results from this study gain important knowledge about the pathogenesis of P. multocida causing infections in both animals and humans.

Two Bordetella bronchiseptica attenuated vaccine candidates confer protection against lethal challenge with B. Bronchiseptica and Pasteurella multocida toxin in mouse models

Vaccine · 2022-05-20 · 10 citations

Development of an Online Tool for Pasteurella multocida Genotyping and Genotypes of Pasteurella multocida From Different Hosts

Frontiers in Veterinary Science · 2021-12-17 · 9 citations

Pasteurella multocida is a versatile zoonotic pathogen. Multiple systems have been applied to type P. multocida from different diseases in different hosts. Recently, we found that assigning P. multocida strains by combining their capsular, lipopolysaccharide, and MLST genotypes (marked as capsular: lipopolysaccharide: MLST genotype) could help address the biological characteristics of P. multocida circulation in different hosts. However, there is still lack of a rapid and efficient tool to diagnose P. multocida according to this system. Here, we developed an intelligent genotyping platform PmGT for P. multocida strains according to their whole genome sequences using the web 2.0 technologies. By using PmGT, we determined capsular genotypes, LPS genotypes, and MLST genotypes as well as the main virulence factor genes (VFGs) of P. multocida isolates from different host species based on their whole genome sequences published on NCBI. The results revealed a closer association between the genotypes and pasteurellosis rather than between genotypes and host species. With the advent of high-quality, inexpensive DNA sequencing, PmGT represents a more efficient tool for P. multocida diagnosis in both epidemiological studies and clinical settings.