Pseudomonas aeruginosa virulence attenuation by inhibiting siderophore functions

Siderophore-Mediated Cooperation in Anammox Consortia

It has been widely accepted that iron plays an important role in stimulating the activity of anammox bacteria, which contain many iron clusters for electron transport in cells. However, whether anammox bacteria could directly use and how to uptake Fe(III) have been long-time ignored. Here, we found that micrometer-scale magnetite with the size of 10-20 μm significantly promoted the anammox bacterial activity by iron core and iron uptake. Anammox bacteria cannot utilize Fe(III) directly as they are unable to secrete siderophore for the extracellular Fe(III) transfer to intracellular. In anaerobic anammox consortia at the presence of magnetite, siderophore synthesis bacteria belonging to Alphaproteobacteria, Candidate phylum, and Chloroflexi secreted abundant siderophores, which combined with Fe(III) ionized from magnetite to form siderophore-Fe(III) complexes. These complexes were then used by anammox bacteria via a specific outer membrane receptor and transported by the transporter protein to the periplasm, further releasing Fe(III). Cytochrome c was then formed by the siderophore-Fe(III) complex reduction, for assimilation and synthesis of Fe-S protein and heme B in anammox bacteria to increase electron transfer capability. This study reveals the siderophore-mediated bacterial cooperation in anammox consortia for Fe(III) assimilation and implies the important role of siderophore-mediated cooperation in driving nitrogen conversion in the artificial or natural system.

CMCS-PVA@CA hydrogel dressing: A promoter of wound healing with MRSA virulence attenuation function

Traditional wound dressings, primarily centered on antimicrobial or bactericidal strategies, have inadvertently contributed to the rise of drug-resistant bacterial colonies at wound sites, thus prolonging the healing process. In this study, we developed an innovative hydrogel dressing, CMCS-PVA@CA, incorporating carboxymethyl chitosan (CMCS), polyvinyl alcohol (PVA), and cichoric acid (CA), specifically designed to treat skin wounds infected with methicillin-resistant Staphylococcus aureus (MRSA). Computational biology analyses reveal that CA exerts substantial anti-virulence activity by targeting serine/threonine phosphatase (Stp1), achieving an IC50 of 3.912 μM, thereby mitigating MRSA pathogenicity. Notably, CA lacks intrinsic antibacterial properties, minimizing the risk of fostering drug resistance. Furthermore, CMCS-PVA@CA demonstrates effective wound healing acceleration and meets clinical application standards, with its robust mechanical properties enhancing patient comfort. In essence, this study presents CMCS-PVA@CA as a promising hydrogel dressing offering a viable solution for treating drug-resistant bacterial infections in skin wounds.

Xenosiderophores: bridging the gap in microbial iron acquisition strategies

Microorganisms acquire iron from surrounding environment through specific iron chelators known as siderophores that can be of self-origin or synthesized by neighboring microbes. The latter are termed as xenosiderophores. The acquired iron supports their growth, survival, and pathogenesis. Various microorganisms possess the ability to utilize xenosiderophores, a mechanism popularly termed as 'siderophore piracy' besides synthesizing their own siderophores. This adaptability allows microorganisms to conserve energy by reducing the load of siderogenesis. Owing to the presence of xenosiderophore transport machinery, these microbial systems can be used for targeting antibiotics-siderophore conjugates to control pathogenesis and combat antimicrobial resistance. This review outlines the significance of xenosiderophore utilization for growth, stress management and virulence. Siderogenesis and the molecular mechanism of its uptake by related organisms have been discussed vividly. It focuses on potential applications like disease diagnostics, drug delivery, and combating antibiotic resistance. In brief, this review highlights the importance of xenosiderophores projecting them beyond their role as mere iron chelators.

Exploring the antivirulence potential of phenolic compounds to inhibit quorum sensing in Pseudomonas aeruginosa

Bacteria coordinate gene expression in a cell density-dependent manner in a communication process called quorum sensing (QS). The expression of virulence factors, biofilm formation and enzyme production are QS-regulated phenotypes that can interfere in human health. Due to this importance, there is great interest in inhibiting QS, comprising an anti-virulence strategy. This work aimed to evaluate the effect of selected phenolic compounds on the inhibition of QS-regulated phenotypes in Pseudomonas aeruginosa PAO1, using concentrations that do not interfere in bacterial growth. This is one of the main premises for studying the effect of compounds on QS. Firstly, an in-silico study with the LasR and RhlR proteins of P. aeruginosa by molecular docking of 82 phenolic compounds was performed. Then, a screening with 13 selected phenolic compounds was performed, using biosensor strains P. aeruginosa lasB-gfp and P. aeruginosa rhlA-gfp, which emit fluorescence when the QS system is activated. From this assay, eight compounds were selected and evaluated for inhibition of pyocyanin, rhamnolipids, proteases, elastase, and motility. The compounds variably inhibited the evaluated virulence factors. The greatest inhibitions were observed for swarming motility, achieving inhibition rates of up to 50% for baicalein (500 µM) and curcumin (50 µM). Notably, curcumin showed satisfactory inhibition for all phenotypes even at lower concentrations (12.5 to 50 µM) compared to the other compounds (125 to 500 µM). Four compounds - rosmarinic acid, baicalein, curcumin, and resveratrol - were finally tested against biofilm formation observed by optical microscopy. This study demonstrated that phenolic compounds exhibit strong in silico binding to P. aeruginosa LasR and RhlR proteins and variably inhibit QS-regulated phenotypes in vitro. Although no biofilm inhibition was observed, future studies combining compounds and exploring molecular mechanisms are recommended. These findings highlight the biotechnological potential of phenolic compounds for future applications in the food, clinical, and pharmaceutical fields.

Bacterial siderophores: diversity, uptake pathways and applications

Iron is an essential nutrient for the growth, survival and virulence of almost all bacteria. To access iron, many bacteria produce siderophores, molecules with a high affinity for iron. Research has highlighted substantial diversity in the chemical structure of siderophores produced by bacteria, as well as remarkable variety in the molecular mechanisms involved in strategies for acquiring iron through these molecules. The metal-chelating properties of siderophores, characterized by their high affinity for iron and ability to chelate numerous other metals (albeit with lower affinity compared with iron), have also generated interest in diverse fields. Siderophores find applications in the environment, such as in bioremediation and agriculture, in which emerging and innovative strategies are being developed to address pollution and enhance nutrient availability for plants. Moreover, in medicine, siderophores could be used as a tool for novel antimicrobial therapies and medical imaging, as well as in haemochromatosis, thalassemia or cancer treatments. This Review offers insights into the diversity of siderophores, highlighting their potential applications in environmental and medical contexts.

Leveraging bacteria-inspired nanomaterials for targeted controlling biofilm and virulence properties of Pseudomonas aeruginosa

Pseudomonas aeruginosa is an opportunistic pathogen designated as a high-priority pathogen because of its role in major healthcare-associated and nosocomial infections. Biofilm production by these bacteria is one of the adaptive resistance mechanisms to traditional antibiotics, making treatment challenging, especially for immunocompromised patients. P. aeruginosa also produces a variety of virulence factors, which aid in invasion, adhesion, persistence, and immune system protection. Recent advances in nanotechnology-based therapy, notably the application of bioinspired metal and metal-oxide nanomaterials, have been seen as a viable way to control P. aeruginosa biofilm and virulence. Because of its ease of growth and culture, synthesizing metal and metal-oxide nanomaterials using bacterial species has become one of the most environmentally benign green synthesis options. The application of bacterial-inspired nanomaterials is particularly successful for targeted control of P. aeruginosa infection due to interactions with cell membrane components and transport systems. This paper delves into and provides a complete overview of the application of bacterial-inspired metal and metal-oxide nanomaterials to treat P. aeruginosa infection by targeting biofilm and virulence characteristics. The review focused on synthesizing and applying gold, silver, copper, iron, magnetite, and zinc oxide nanomaterials to mitigate P. aeruginosa biofilm and virulence. The underlying mechanism of these metal and metal-oxide nanoparticles in relation to biofilm and virulence features has also been thoroughly discussed. The current review introduces novel approaches to treating and controlling drug-resistant P. aeruginosa using bacterial-inspired nanomaterials as a targeted therapeutic strategy.

Multifaceted strategies for alleviating Pseudomonas aeruginosa infection by targeting protease activity: Natural and synthetic molecules

Pseudomonas aeruginosa has become a top-priority pathogen in the health sector because it is ubiquitous, has high metabolic/genetic versatility, and is identified as an opportunistic pathogen. The production of numerous virulence factors by P. aeruginosa was reported to act individually or cooperatively to make them robots invasion, adherences, persistence, proliferation, and protection against host immune systems. P. aeruginosa produces various kinds of extracellular proteases such as alkaline protease, protease IV, elastase A, elastase B, large protease A, Pseudomonas small protease, P. aeruginosa aminopeptidase, and MucD. These proteases effectively allow the cells to invade and destroy host cells. Thus, inhibiting these protease activities has been recognized as a promising approach to controlling the infection caused by P. aeruginosa. The present review discussed in detail the characteristics of these proteases and their role in infection to the host system. The second part of the review discussed the recent updates on the multiple strategies for attenuating or inhibiting protease activity. These strategies include the application of natural and synthetic molecules, as well as metallic/polymeric nanomaterials. It has also been reported that a propeptide present in the middle domain of protease IV also attenuates the virulence properties and infection ability of P. aeruginosa.

Roles of Pseudomonas aeruginosa siderophores in interaction with prokaryotic and eukaryotic organisms

Pseudomonas aeruginosa is an opportunistic pathogen that produces two types of siderophores, pyoverdine and pyochelin, that play pivotal roles in iron scavenging from the environment and host cells. P. aeruginosa siderophores can serve as virulence factors and perform various functions. Several bacterial and fungal species are likely to interact with P. aeruginosa due to its ubiquity in soil and water as well as its potential to cause infections in plants, animals, and humans. Siderophores produced by P. aeruginosa play critical roles in iron scavenging for prokaryotic species (bacteria) and eukaryotic hosts (fungi, animals, insects, invertebrates, and plants) as well. This review provides a comprehensive discussion of the role of P. aeruginosa siderophores in interaction with prokaryotes and eukaryotes as well as their underlying mechanisms of action. The evolutionary relationship between P. aeruginosa siderophore recognition receptors, such as FpvA, FpvB, and FptA, and those of other bacterial species has also been investigated.

Natural and synthetic molecules with potential to enhance biofilm formation and virulence properties in Pseudomonas aeruginosa

Pseudomonas aeruginosa can efficiently adapt to changing environmental conditions due to its ubiquitous nature, intrinsic/acquired/adaptive resistance mechanisms, high metabolic versatility, and the production of numerous virulence factors. As a result, P. aeruginosa becomes an opportunistic pathogen, causing chronic infection in the lungs and several organs of patients suffering from cystic fibrosis. Biofilm established by P. aeruginosa in host tissues and medical device surfaces has been identified as a major obstruction to antimicrobial therapy. P. aeruginosa is very likely to be closely associated with the various microorganisms in the host tissues or organs in a pathogenic or nonpathogenic behavior. Aside from host-derived molecules, other beneficial and pathogenic microorganisms produce a diverse range of secondary metabolites that either directly or indirectly favor the persistence of P. aeruginosa. Thus, it is critical to understand how P. aeruginosa interacts with different molecules and ions in the host and abiotic environment to produce extracellular polymeric substances and virulence factors. Thus, the current review discusses how various natural and synthetic molecules in the environment induce biofilm formation and the production of multiple virulence factors.

Total substitution and partial modification of the set of non-ribosomal peptide synthetases clusters lead to pyoverdine diversity in the Pseudomonas fluorescens complex

Pyoverdines are high affinity siderophores produced by most Pseudomonas with a wide role in microbial interspecies interactions. They are primarily composed of a conserved chromophore moiety, an acyl side chain and a peptide backbone which may be highly variable among strains. Upon ferric iron sequestration, pyoverdines are internalized through specialized receptors. The peptide precursor of pyoverdine, termed ferribactin, is synthesized by a set of non-ribosomal peptide synthetase (NRPS) enzymes and further modified by tailoring enzymes. While PvdL, the NRPS responsible for the synthesis of the peptide moiety that derives into the chromophore is conserved, the NRPSs for the peptide backbone are different across fluorescent Pseudomonas. Although the variation of pyoverdine is a widely recognized characteristic within the genus, the evolutionary events associated with the diversity and distribution of this trait remain mostly unknown. This study analyzed the NRPSs clusters for the biosynthesis of the peptide backbone of ferribactin in the genomes of a representative subset of strains of the Pseudomonas fluorescens complex. Bioinformatic analysis of the specificity of adenylation domains of the NRPSs allowed the prediction of 30 different pyoverdine variants. Phylogenetic reconstruction and mapping of the NRPS clusters pinpointed two different general levels of modifications. In the first level, a complete replacement of the set of NRPRs by horizontal transfer occurs. In the second level, the original set of NRPSs is modified through different mechanisms, including partial substitution of the NRPS genes by horizontal transfer, adenylation domain specificity change or NRPS accessory domain gain/loss.

Two cinnamoyl hydroxamates as potential quorum sensing inhibitors against Pseudomonas aeruginosa

Introduction

Pseudomonas aeruginosa is a ubiquitous pathogen that causes various infectious diseases through the regulation of quorum sensing (QS). The strategy of interfering with the QS systems of P. aeruginosa, coupled with a reduction in the dosage of conventional antibiotics, presents a potential solution to treating infection and mitigating antibiotic resistance. In this study, seven cinnamoyl hydroxamates were synthesized to evaluate their inhibitory effects on QS of P. aeruginosa. Among these cinnamic acid derivatives, we found cinnamoyl hydroxamic acid (CHA) and 3-methoxy-cinnamoyl hydroxamic acid (MCHA) were the two most effective candidates. Furtherly, the effect of CHA and MCHA on the production of virulence factors and biofilm of P. aeruginosa were evaluated. Ultimately, our study may offer promising potential for treating P. aeruginosa infections and reducing its virulence.

Methods

The disc diffusion test were conducted to evaluate inhibitory effects on QS of seven cinnamoyl hydroxamates. The influence of CHA and MCHA on the production of virulence and flagellar motility of P. aeruginosa was furtherly explored. Scanning electron microscopy (SEM) experiment were conducted to evaluate the suppression of CHA and MCHA on the formed biofilm of P. aeruginosa. RT-qPCR was used to detect rhlI, lasA, lasB, rhlA, rhlB, and oprL genes in P. aeruginosa. In silico docking study was performed to explore the molecular mechanism of CHA and MCHA. The synergistic effects of CHA with gentamicin were detected on biofilm cell dispersal.

Result

After treatment of CHA or MCHA, the production of multiple virulence factors, including pyocyanin, proteases, rhamnolipid, and siderophore, and swimming and swarming motilities in P. aeruginosa were inhibited significantly. And our results showed CHA and MCHA could eliminate the formed biofilm of P. aeruginosa. RT-qPCR revealed that CHA and MCHA inhibited the expression of QS related genes in P. aeruginosa. Molecular docking indicated that CHA and MCHA primarily inhibited the RhlI/R system in P. aeruginosa by competing with the cognate signaling molecule C4-HSL.Additionally, CHA exhibited potent synergistic effects with gentamicin on biofilm cell dispersal.

Discussion

P. aeruginosa is one of the most clinically and epidemiologically important bacteria and a primary cause of catheter-related urinary tract infections and ventilator-associated pneumonia. This study aims to explore whether cinnamoyl hydroxamates have inhibitory effects on QS. And our results indicate that CHA and MCHA, as two novel QSIs, offer promising potential for treating P. aeruginosa infections and reducing its virulence.

Attenuation of biofilm and virulence factors of Pseudomonas aeruginosa by tetramethylpyrazine-gold nanoparticles

Pseudomonas aeruginosa is often identified as the causative agent in nosocomial infections. Their adapted resistance makes them strong towards antimicrobial treatments. They protect and empower their survival behind strong biofilm architecture that works as their armor toward antimicrobial therapy. Additionally, P. aeruginosa generates virulence factors, contributing to chronic infection and recalcitrant phenotypic characteristics. The current study utilizes the benevolence of nanotechnology to develop an alternate technique to control the spreading of P. aeruginosa by limiting its biofilm and virulence development. This study used a natural compound, tetramethylpyrazine, to generate gold nanoparticles. Tetramethylpyrazine-gold nanoparticles (Tet-AuNPs) were presented in spherical shapes, with an average size of 168 ± 52.49 nm and a zeta potential of -12.22 ± 2.06 mV. The minimum inhibition concentration (MIC) of Tet-AuNPs that proved more than 90 % effective in inhibiting P. aeruginosa was 256 μg/mL. Additionally, it also shows antibacterial activities against Staphylococcus aureus (MIC, 256 μg/mL), Streptococcus mutans (MIC, 128 μg/mL), Klebsiella pneumoniae (MIC, 128 μg/mL), Listeria monocytogenes (MIC, 256 μg/mL), and Escherichia coli (MIC, 256 μg/mL). The sub-MIC values of Tet-AuNPs significantly inhibited the early-stage biofilm formation of P. aeruginosa. Moreover, this concentration strongly affected hemolysis, protease activity, and different forms of motilities in P. aeruginosa. Additionally, Tet-AuNPs destroyed the well-established mature biofilm of P. aeruginosa. The expression of genes linked with the biofilm formation and virulence in P. aeruginosa treated with sub-MIC doses of Tet-AuNPs was shown to be significantly suppressed. Gene expression studies support biofilm- and virulence-suppressing effects of Tet-AuNPs at the phenotypic level.

Exploring the Biological Pathways of Siderophores and Their Multidisciplinary Applications: A Comprehensive Review

Siderophores are a class of small molecules renowned for their high iron binding capacity, essential for all life forms requiring iron. This article provides a detailed review of the diverse classifications, and biosynthetic pathways of siderophores, with a particular emphasis on siderophores synthesized via nonribosomal peptide synthetase (NRPS) and non-NRPS pathways. We further explore the secretion mechanisms of siderophores in microbes and plants, and their role in regulating bioavailable iron levels. Beyond biological functions, the applications of siderophores in medicine, agriculture, and environmental sciences are extensively discussed. These applications include biological pest control, disease treatment, ecological pollution remediation, and heavy metal ion removal. Through a comprehensive analysis of the chemical properties and biological activities of siderophores, this paper demonstrates their wide prospects in scientific research and practical applications, while also highlighting current research gaps and potential future directions.

The highly effective cadmium-resistant mechanism of Pseudomonas aeruginosa and the function of pyoverdine induced by cadmium

Pyoverdine (PVD) plays an important role in reducing cadmium (Cd) accumulation in plants. Some Pseudomonas aeruginosa (P. aeruginosa) species can produce PVD under Cd(Π) stress. However, the function of Cd(Π)-induced PVD remains unclear. In this study, we isolated a highly effective Cd(Π)-resistant P. aeruginosa which can secrete PVD under Cd(Π) stress and found that PVD secretion has a dose-dependent relationship with Cd(Π) concentration. PVD can form a PVD-Cd complex with Cd(Π), though the PVD-Cd complex is unable to be adsorbed by the cell or enter the cell, so the complexation of PVD and Cd(Π) impedes Cd(Π) adsorption on the cell surface and alleviates the oxidative stress, lipid peroxidation, and morphological destruction of the cell caused by Cd(Π) and effectively improves the resistance of P. aeruginosa to Cd(Π). In summary, our research results indicate that the Cd(Π) resistance mechanism of P. aeruginosa screened is the complexation of PVD for Cd(Π) and the adsorption of bacteria for Cd(Π); furthermore, PVD plays an important role in improving the Cd(Π)-resistant ability of bacteria. This study provides a deeper understanding of the highly effective Cd(Π) resistance mechanism of P. aeruginosa and the function of Cd(Π)-induced PVD in bacteria.

Antimicrobial, antibiofilm, and antivirulence properties of Eisenia bicyclis-extracts and Eisenia bicyclis-gold nanoparticles towards microbial pathogens

Nanomaterials derived from seaweed have developed as an alternative option for fighting infections caused by biofilm-forming microbial pathogens. This research aimed to discover potential seaweed-derived nanomaterials with antimicrobial and antibiofilm action against bacterial and fungal pathogens. Among seven algal species, the extract from Eisenia bicyclis inhibited biofilms of Klebsiella pneumoniae, Staphylococcus aureus, and Listeria monocytogenes most effectively at sub-MIC levels. As a result, in the present study, E. bicyclis was chosen as a prospective seaweed for producing E. bicyclis-gold nanoparticles (EB-AuNPs). Furthermore, the mass spectra of E. bicyclis reveal the presence of a number of potentially beneficial chemicals. The polyhedral shape of the synthesized EB-AuNP with a size value of 154.74 ± 33.46 nm was extensively described. The lowest inhibitory concentration of EB-AuNPs against bacterial pathogens (e.g., L.monocytogenes, S. aureus, Pseudomonas aeruginosa, and K. pneumoniae) and fungal pathogens (Candida albicans) ranges from 512 to >2048 μg/mL. Sub-MIC of EB-AuNPs reduces biofilm formation in P. aeruginosa, K. pneumoniae, L. monocytogenes, and S. aureus by 57.22 %, 58.60 %, 33.80 %, and 91.13 %, respectively. EB-AuNPs eliminate the mature biofilm of K. pneumoniae at > MIC, MIC, and sub-MIC concentrations. Furthermore, EB-AuNPs at the sub-MIC level suppress key virulence factors generated by P. aeruginosa, including motility, protease activity, pyoverdine, and pyocyanin, whereas it also suppresses the production of staphyloxanthin virulence factor from S. aureus. The current research reveals that seaweed extracts and a biocompatible seaweed-AuNP have substantial antibacterial, antibiofilm, and antivirulence actions against bacterial and fungal pathogens.

Virulence of Pseudomonas aeruginosa in Cystic Fibrosis: Relationships between Normoxia and Anoxia Lifestyle

The airways of cystic fibrosis (CF) patients are colonized by many pathogens and the most common is Pseudomonas aeruginosa, an environmental pathogen that is able to infect immunocompromised patients thanks to its ability to develop resistance to conventional antibiotics. Over 12% of all patients colonized by P. aeruginosa harbour multi-drug resistant species. During airway infection in CF, P. aeruginosa adopts various mechanisms to survive in a hostile ecological niche characterized by low oxygen concentration, nutrient limitation and high osmotic pressure. To this end, P. aeruginosa uses a variety of virulence factors including pigment production, biofilm formation, motility and the secretion of toxins and proteases. This study represents the first report that systematically analyzes the differences in virulence features, in normoxia and anoxia, of clinical P. aeruginosa isolated from CF patients, characterized by multi- or pan-drug antibiotic resistance compared to antibiotic sensitive strains. The virulence features, such as biofilm formation, protease secretion and motility, are highly diversified in anaerobiosis, which reflects the condition of chronic CF infection. These findings may contribute to the understanding of the real-world lifestyle of pathogens isolated during disease progression in each particular patient and to assist in the design of therapeutic protocols for personalized medicine.

Attenuation of biofilm and quorum sensing regulated virulence factors of an opportunistic pathogen Pseudomonas aeruginosa by phytofabricated silver nanoparticles

Green-synthesized nanoparticles provide an effective strategy for inhibiting microbial pathogenesis by affecting biofilm formation, quorum sensing (QS), and other surface properties of microorganisms. QS is a density-dependent communication signaling cascade that regulates biofilm formation and other pathogenic factors of Pseudomonas aeruginosa. In this context, the effect of phytofabricated silver nanoparticles (CC-AgNPs) synthesized using Cuphea carthagenensis extract on biofilm, QS, and QS-dependent virulence factors of P. aeruginosa were evaluated in this study. CC-AgNPs demonstrated significant attenuation of biofilm, QS, and QS-dependent virulence factors at sub-MICs. A significant inhibition of 88.39 ± 4.32 %, 79.64 ± 3.31 %, 73.07 ± 3.0 %, and 61.67 ± 1.5 % of biofilm formation, quorum sensing, pyocyanin, and LasB elastase, respectively was reported in the study at 20 μg/mL. The study also demonstrated a significant reduction of LasA Staphylolytic activity and 91.37 ± 1.05 % exoprotease production in comparison to untreated control. The lower concentrations of CC-AgNPs also demonstrated significant attenuation of biofilm and other virulence factors suggesting the strong potency of NPs against P. aeruginosa. XTT analysis reported the effect of CC-AgNPs on sessile cells of P. aeruginosa without impacting growth of planktonic cells at sub-MICs. Cell-proliferation study in human cell lines (HEK 293 and Caco-2 cells) demonstrated the safe nature of CC-AgNPs at tested concentrations. This study is novel in a way that environmentally friendly CC-AgNPs were used to inhibit QS at sub-MICs without killing the tested strains, therefore, could be developed as an anti-virulent drug to overcome biofilm and antimicrobial resistance problems.

The mechanism of ferroptosis and its related diseases

Ferroptosis, a regulated form of cellular death characterized by the iron-mediated accumulation of lipid peroxides, provides a novel avenue for delving into the intersection of cellular metabolism, oxidative stress, and disease pathology. We have witnessed a mounting fascination with ferroptosis, attributed to its pivotal roles across diverse physiological and pathological conditions including developmental processes, metabolic dynamics, oncogenic pathways, neurodegenerative cascades, and traumatic tissue injuries. By unraveling the intricate underpinnings of the molecular machinery, pivotal contributors, intricate signaling conduits, and regulatory networks governing ferroptosis, researchers aim to bridge the gap between the intricacies of this unique mode of cellular death and its multifaceted implications for health and disease. In light of the rapidly advancing landscape of ferroptosis research, we present a comprehensive review aiming at the extensive implications of ferroptosis in the origins and progress of human diseases. This review concludes with a careful analysis of potential treatment approaches carefully designed to either inhibit or promote ferroptosis. Additionally, we have succinctly summarized the potential therapeutic targets and compounds that hold promise in targeting ferroptosis within various diseases. This pivotal facet underscores the burgeoning possibilities for manipulating ferroptosis as a therapeutic strategy. In summary, this review enriched the insights of both investigators and practitioners, while fostering an elevated comprehension of ferroptosis and its latent translational utilities. By revealing the basic processes and investigating treatment possibilities, this review provides a crucial resource for scientists and medical practitioners, aiding in a deep understanding of ferroptosis and its effects in various disease situations.

Recombineering enables genome mining of novel siderophores in a non-model Burkholderiales strain

Iron is essential for bacterial survival, and most bacteria capture iron by producing siderophores. Burkholderiales bacteria produce various types of bioactive secondary metabolites, such as ornibactin and malleobactin siderophores. In this study, the genome analysis of Burkholderiales genomes showed a putative novel siderophore gene cluster crb, which is highly similar to the ornibactin and malleobactin gene clusters but does not have pvdF, a gene encoding a formyltransferase for N-δ‑hydroxy-ornithine formylation. Establishing the bacteriophage recombinase Redγ-Redαβ7029 mediated genome editing system in a non-model Burkholderiales strain Paraburkholderia caribensis CICC 10960 allowed the rapid identification of the products of crb gene cluster, caribactins A-F (1-6). Caribactins contain a special amino acid residue N-δ‑hydroxy-N-δ-acetylornithine (haOrn), which differs from the counterpart N-δ‑hydroxy-N-δ-formylornithine (hfOrn) in ornibactin and malleobactin, owing to the absence of pvdF. Gene inactivation showed that the acetylation of hOrn is catalyzed by CrbK, whose homologs probably not be involved in the biosynthesis of ornibactin and malleobactin, showing possible evolutionary clues of these siderophore biosynthetic pathways from different genera. Caribactins promote biofilm production and enhance swarming and swimming abilities, suggesting that they may play crucial roles in biofilm formation. This study also revealed that recombineering has the capability to mine novel secondary metabolites from non-model Burkholderiales species.

The Gene paaZ of the Phenylacetic Acid (PAA) Catabolic Pathway Branching Point and ech outside the PAA Catabolon Gene Cluster Are Synergistically Involved in the Biosynthesis of the Iron Scavenger 7-Hydroxytropolone in Pseudomonas donghuensis HYS

The newly discovered iron scavenger 7-hydroxytropolone (7-HT) is secreted by Pseudomonas donghuensis HYS. In addition to possessing an iron-chelating ability, 7-HT has various other biological activities. However, 7-HT's biosynthetic pathway remains unclear. This study was the first to report that the phenylacetic acid (PAA) catabolon genes in cluster 2 are involved in the biosynthesis of 7-HT and that two genes, paaZ (orf13) and ech, are synergistically involved in the biosynthesis of 7-HT in P. donghuensis HYS. Firstly, gene knockout and a sole carbon experiment indicated that the genes orf17-21 (paaEDCBA) and orf26 (paaG) were involved in the biosynthesis of 7-HT and participated in the PAA catabolon pathway in P. donghuensis HYS; these genes were arranged in gene cluster 2 in P. donghuensis HYS. Interestingly, ORF13 was a homologous protein of PaaZ, but orf13 (paaZ) was not essential for the biosynthesis of 7-HT in P. donghuensis HYS. A genome-wide BLASTP search, including gene knockout, complemented assays, and site mutation, showed that the gene ech homologous to the ECH domain of orf13 (paaZ) is essential for the biosynthesis of 7-HT. Three key conserved residues of ech (Asp39, His44, and Gly62) were identified in P. donghuensis HYS. Furthermore, orf13 (paaZ) could not complement the role of ech in the production of 7-HT, and the single carbon experiment indicated that paaZ mainly participates in PAA catabolism. Overall, this study reveals a natural association between PAA catabolon and the biosynthesis of 7-HT in P. donghuensis HYS. These two genes have a synergistic effect and different functions: paaZ is mainly involved in the degradation of PAA, while ech is mainly related to the biosynthesis of 7-HT in P. donghuensis HYS. These findings complement our understanding of the mechanism of the biosynthesis of 7-HT in the genus Pseudomonas.

A Comprehensive Review on the Roles of Metals Mediating Insect-Microbial Pathogen Interactions

Insects and microbial pathogens are ubiquitous and play significant roles in various biological processes, while microbial pathogens are microscopic organisms that can cause diseases in multiple hosts. Insects and microbial pathogens engage in diverse interactions, leveraging each other's presence. Metals are crucial in shaping these interactions between insects and microbial pathogens. However, metals such as Fe, Cu, Zn, Co, Mo, and Ni are integral to various physiological processes in insects, including immune function and resistance against pathogens. Insects have evolved multiple mechanisms to take up, transport, and regulate metal concentrations to fight against pathogenic microbes and act as a vector to transport microbial pathogens to plants and cause various plant diseases. Hence, it is paramount to inhibit insect-microbe interaction to control pathogen transfer from one plant to another or carry pathogens from other sources. This review aims to succinate the role of metals in the interactions between insects and microbial pathogens. It summarizes the significance of metals in the physiology, immune response, and competition for metals between insects, microbial pathogens, and plants. The scope of this review covers these imperative metals and their acquisition, storage, and regulation mechanisms in insect and microbial pathogens. The paper will discuss various scientific studies and sources, including molecular and biochemical studies and genetic and genomic analysis.

Colostrum and Lactoferrin Protect against Side Effects of Therapy with Antibiotics, Anti-inflammatory Drugs and Steroids, and Psychophysical Stress: A Comprehensive Review

In this article, we review the benefits of applying bovine colostrum (BC) and lactoferrin (LF) in animal models and clinical trials that include corticosteroid application and psychic stress, treatment with non-steroid anti-inflammatory drugs (NSAIDs) and antibiotics. A majority of the reported investigations were performed with native bovine or recombinant human LF, applied alone or in combination with probiotics, as nutraceutics and diet supplements. Apart from reducing adverse side effects of the applied therapeutics, BC and LF augmented their efficacy and improved the wellness of patients. In conclusion, LF and complete native colostrum, preferably administered with probiotic bacteria, are highly recommended for inclusion in therapeutic protocols in NSAIDs and corticosteroid anti-inflammatory, as well as antibiotic, therapies. These colostrum-based products can also be of value for individuals subjected to prolonged psychophysical stress (mediated by endogenous corticosteroids), especially at high ambient temperatures (soldiers and emergency services), as well as physically active people and training athletes. They are also recommended for patients during recovery from trauma and surgery, which are always associated with severe psychophysical stress.