Search Results (159)

Periodontal diseases are highly prevalent in dogs and intricately interconnected with the composition and functional attributes of the oral microbiota. The demand for non-invasive interventions to support oral health presents an opportunity for functional ingredients. The novel postbiotic heat-treated (HT) Lactiplantibacillus plantarum CECT 9161 inhibited growth and biofilm formation of oral microorganisms in vitro. The in vitro growth of saliva-derived biofilms was also inhibited and revealed microbiome modulation. Two doses of the postbiotic (LOW: 5 mg dog/day, HIGH: 25 mg/dog/day) were assessed in a placebo-controlled, double-blinded, 57-day clinical trial involving 60 dogs. Associations were found between the postbiotic, reduced plaque formation, and modulation of the oral microbiome, including increased abundance of genes involved in denitrification, heme and catechol biosynthesis, and oxidative stress reduction. The results suggest that HT Lactiplantibacillus plantarum CECT 9161 may support oral health in dogs by modifying the microbiome of supragingival plaque and reducing plaque formation. Full article

Apricot bee pollen is an important natural product that exhibits antioxidant, anti-inflammatory, and antimicrobial properties. Deoxynivalenol (DON), one of the most prevalent mycotoxins produced by Fusarium fungi, poses risks to both human and animal reproductive systems. We observed that exposure to DON inhibited cell proliferation and induced apoptosis in bovine granulosa cells (bGCs), accompanied by a significant downregulation of PCNA expression and an upregulation of BAX expression. RNA sequencing analysis revealed that differentially expressed genes (DEGs) were primarily enriched in the oxidation-reduction process, oxidoreductase activity, and steroid biosynthesis. We further confirmed that DON exposure inhibited the production of estrogen and progesterone by decreasing the protein expression levels of CYP19A1 and StAR. Additionally, DON exposure increased the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) in a dose-dependent manner, suggesting that DON induced oxidative stress in bGCs. Importantly, we demonstrated that apricot bee pollen ethanol extract (ABPE) increased the cell viability of bGCs and alleviated the effects of DON-induced cell viability reduction and estrogen dysfunction. Furthermore, ABPE attenuated the DON-induced increase in ROS levels and upregulated the expression of antioxidant-related gene heme oxygenase-1 (HO-1). These results reveal the protective effects of ABPE against DON-induced cell viability reduction, estrogen disorder, and oxidative stress, providing new insights into the potential of bee pollen as a promising natural agent to improve mycotoxin contamination. Full article

Background/Objectives: Isoniazid (INH) and pyrazinamide (PZA) are first-line drugs used to treat tuberculosis (TB), but their use is generally contraindicated in patients with porphyria, a group of metabolic disorders caused by defects in the heme biosynthetic pathway. To investigate the basis for these contraindications, we compared the effects of INH and PZA on the heme biosynthetic pathway in mouse liver. Method: We investigated the hepatic expression and activity of the key enzymes involved in the heme biosynthetic pathway, including aminolevulinic acid synthase 1 (Alas1) and ferrochelatase (Fech). Additionally, we employed a metabolomic approach to analyze liver and fecal samples from the mice treated with INH or PZA. Result: We found that INH, but not PZA, significantly upregulated the expression and activity of Alas1, the rate-limiting enzyme in heme biosynthesis, while concurrently downregulating Fech, which converts protoporphyrin IX (PPIX) to heme. These changes resulted in the accumulation of the toxic intermediate aminolevulinic acid (ALA) and PPIX in the liver of INH-treated mice. In contrast, PZA had no measurable effect on the expression or function of Alas1 or Fech. Conclusions: These findings provide mechanistic insight into INH-induced porphyria exacerbation and suggest that PZA may not carry the same risk, challenging its current contraindication. Full article

Neonatal Meningitis-causing Escherichia coli (NMEC) is the leading cause of neonatal meningitis and exhibits remarkable adaptability to diverse host environments. Understanding its transcriptional responses across different host niches is crucial for deciphering pathogenesis and identifying potential therapeutic targets. We performed a comparative transcriptomic analysis of NMEC RS218, the prototype strain of NMEC, under four distinct host-mimicking conditions: colonic fluid (CF), serum (S), human brain endothelial cells (HBECs), and cerebrospinal fluid (CSF). Differential gene expression analysis was conducted to assess metabolic shifts, virulence factor regulation, and niche-specific adaptation strategies, in which RS218 demonstrated niche-specific transcriptional reprogramming. In CF, genes associated with biofilm formation, motility, efflux pumps, and cell division regulation were upregulated, aiding gut colonization. The serum environment triggered the expression of siderophore-mediated iron acquisition, enterobactin biosynthesis, and heme utilization genes, facilitating immune evasion and bacterial persistence. In HBECs, NMEC upregulated genes linked to nucleoside metabolism, membrane remodeling, pilus organization, and blood–brain barrier (BBB) traversal. In CSF, genes related to oxidative stress resistance, chemotaxis, DNA repair, biofilm formation, and amino acid biosynthesis were enriched, reflecting NMEC’s adaptive mechanisms for survival under nutrient-depleted conditions. Energy-intensive pathways were consistently downregulated across all niches, highlighting the need for an energy conservation strategy. This study provides novel insights into NMEC’s adaptive strategies across different host environments, emphasizing its metabolic flexibility, virulence regulation, and immune evasion mechanisms, offering potential targets for therapeutic intervention. Full article

Background: 5-Aminolevulinic acid (5-ALA) serves as a precursor in the heme biosynthesis pathway, resulting in the selective accumulation of protoporphyrin IX (PpIX) within glioma cells. This property facilitates fluorescence-guided resection (FGR) in high-grade gliomas (HGGs), enhancing surgical precision and oncological results. Nonetheless, its clinical implementation is restricted by factors such as accessibility, cost, and technical limitations. Methods: A systematic review of PubMed literature (2019–2024) was conducted to assess the efficacy of 5-ALA in HGG surgery compared to conventional white light microscopy. Studies focusing on non-neurosurgical applications, pediatric populations, and non-HGG indications were excluded. Results: Nineteen articles met the criteria. Recent studies indicate that 5-ALA-guided resection significantly enhances gross total resection (GTR) rates compared to white light surgery (75.4% vs. 54.3%, p < 0.001). Patients receiving 5-ALA-assisted resection exhibit enhanced progression-free survival (PFS) at 6 months (median 8.1 months compared to 5.4 months, p = 0.002) and overall survival (OS) (median 15.2 months versus 12.3 months, p = 0.008). The necessity for specialized neurosurgical microscopes equipped with blue light filters restricts accessibility, especially in low-resource environments. Recent advancements in fluorescence-enhancing technologies, particularly loupe-based systems, have demonstrated increases in fluorescence intensity by up to tenfold through direct emission. Sodium fluorescein, originally designed for ophthalmological use, has been adapted for enhancing contrast in intracranial tumors; however, its non-specific binding to serum albumin restricts its accuracy in glioma resection. Conclusions: Recent publications demonstrate that 5-ALA fluorescence-guided surgery significantly improves gross total resection rates and survival outcomes in patients with high-grade gliomas. Although it offers clinical advantages, cost and equipment constraints continue to pose substantial obstacles to broad implementation. Additional research is required to enhance fluorescence-guided techniques and increase accessibility in resource-constrained environments. Full article

Currently, various types of myoglobins and hemoglobins are widely used in the fields of food additives and biocatalytic applications. However, the limited availability of heme constrains the biosynthesis of these high-activity hemoproteins in microbial chassis cells. In this work, a new heme synthetic pathway was reconstructed in the mitochondria by eliminating the spatial barrier during heme synthesis in Saccharomyces cerevisiae, resulting in a significant enhancement in intracellular heme supply. To further enhance the supply of the essential precursor for heme synthesis (5-aminolevulinate, ALA), the special ALA exporter in the mitochondrial membrane (Ort1p) was identified and knocked out. Moreover, the mitochondrial heme exporter (Ygr127wp) was overexpressed to promote the transport of heme to the cytoplasm to participate in the synthesis of various myoglobins and hemoglobins. Based on these strategies in the engineered strain, the binding ratios of heme in porcine myoglobin (52.4 ± 4.9%) and soybean hemoglobin (75.5 ± 2.8%) were, respectively, increased by 2.4-fold and 3.6-fold, and the titers of porcine myoglobin (130.5 ± 2.8 mg·L⁻¹) and soybean hemoglobin (152.8 ± 2.6 mg·L⁻¹), respectively, increased by 31.1% and 42.1%. Furthermore, the engineered strain presents great potential in the efficient synthesis of other heme-binding proteins and enzymes in S. cerevisiae. Full article

Ergothioneine (EGT), a natural thiol compound with potent antioxidant properties, exhibits diverse biological functions, including anti-inflammatory, neuroprotective, and cardioprotective effects. Despite its promising health and food applications, current production methods, such as mushroom-based liquid fermentation, are hindered by low yields and complex processes. Advances in biosynthetic fermentation, including heterologous expression of key pathway genes and optimization of cultivation conditions, offer promising solutions to these challenges. Recent discoveries, such as the catalytic efficiency of mononuclear non-heme iron enzymes like Egt1 and EgtB, have streamlined EGT biosynthetic pathways, reducing steps and increasing yield. The compound’s active transport via the OCTN1 protein facilitates its distribution across tissues, enhancing its therapeutic efficacy and potential in functional foods. Currently employed as an antioxidant and antimelanogenic agent in aquatic products, EGT holds vast potential for broader applications in food systems. This review explores the advancements in EGT production and biosynthesis while emphasizing its prospects as a safe, versatile, and effective natural ingredient for health and industrial applications. Full article

Background/Objectives: Eumycetoma, caused by Madurella mycetomatis, is a chronic fungal infection with limited treatment options and increasing drug resistance. CYP51, a key enzyme in ergosterol biosynthesis, is a well-established target for azole antifungals. However, existing azole drugs demonstrate limited efficacy in treating eumycetoma. Microbial-based natural products, with their structural diversity and bioactivity, offer a promising source for novel CYP51 inhibitors. This study aimed to identify potential Madurella mycetomatis CYP51 inhibitors from microbial natural products using molecular docking, MM-GBSA calculations, ADMET analysis, and molecular dynamics (MD) simulations. Methods: Virtual screening was conducted on a library of microbial-based natural products using an in-house homology model of Madurella mycetomatis CYP51, with itraconazole as the reference drug. The top compounds from initial docking were refined through Standard and Extra Precision docking. MM-GBSA calculations assessed binding affinities, and ADMET analysis evaluated drug-like properties. Compounds with favorable properties underwent MD simulations. Results: The computational investigations identified 34 compounds with better docking scores and binding affinity than itraconazole. Of these, 9 compounds interacted with the heme group and key residues in the active site of Madurella mycetomatis CYP51. In silico pharmacokinetic profiling identified 3 compounds as promising candidates, and MD simulations confirmed their potential as CYP51 inhibitors. Conclusions: The study highlights microbial-derived natural products, particularly monacyclinone G, H, and I, as promising candidates for Madurella mycetomatis CYP51 inhibition, with the potential for treating eumycetoma, requiring further experimental validation. Full article

Maximal safe surgical resection is the gold standard in brain tumor surgery. Fluorescence-guided surgery (FGS) is one of many intraoperative techniques that have been designed with the intention of accomplishing this goal. 5-aminolevulinic acid (5-ALA) is one of the main fluorophores that facilitates FGS in neurosurgical oncology. Multiple different types of brain tumors can take in and metabolize 5-ALA into protoporphyrin IX (PpIX) through the mitochondria heme biosynthesis pathway. PpIX then selectively accumulates in brain tumor cells due to decreased ferrochelatase activity and emits red fluorescence (630–720 nm) when excited with blue light (375–440 nm). This mechanism allows neurosurgeons to better visualize tumor burden and increase extent of resection while preserving non-cancerous brain parenchyma and, specifically, eloquent white matter tracts, if combined with mapping techniques, thereby minimizing morbidity while improving survival. While 5-ALA use is well established in the treatment of high-grade gliomas, its applicability in recurrent high-grade and non-enhancing IDH-mutant low-grade gliomas, as well as non-glial tumors, is less established or limited by certain features of their cellular and molecular biology. This review aims to discuss the current landscape of 5-ALA utility across the diverse range of brain tumors, practical considerations that optimize its current use in neurosurgery, modern clinical limitations of 5-ALA, and how its application can be expanded by combining its use with other techniques that overcome current limitations. Full article

Cytochrome P450 enzymes (CYPs) are versatile heme-containing monooxygenases involved in the metabolism of endogenous and exogenous compounds, as well as natural product biosynthesis. Their ability to catalyze regio- and stereoselective oxidation reactions makes them valuable in pharmaceuticals, fine chemicals, and biocatalysis. However, wild-type CYPs suffer from low catalytic efficiency, limited substrate specificity, and instability under industrial conditions. Recent advances in protein engineering—rational design, semi-rational design, and directed evolution—have enhanced their activity, stability, and substrate scope. These strategies have enabled CYPs to be engineered for applications like C–H functionalization, carbene transfer, and complex molecule biosynthesis. Despite progress, challenges remain in optimizing efficiency, expanding substrate ranges, and scaling production for industrial use. Future directions include integrating CYPs with other biocatalysts, improving high-throughput screening, and applying machine learning to enzyme design. This review highlights recent developments and the promising future of engineered CYPs in sustainable chemistry, drug development, and high-value chemical production. Full article

Ergosterol plays a dual role in fungal pathogenesis and azole resistance, driving key advancements in the understanding of its biosynthesis regulation. This review integrates the latest research progress on the regulation of fungal ergosterol biosynthesis and its role in drug resistance and pathogenicity. We comprehensively discuss the functions of key enzymes (such as Erg11p/Cyp51A, Erg6p, Erg3p, and Erg25p) in the mevalonate, late, and alternative pathways. Notably, we highlight the complex regulation of cyp51A expression by factors such as SrbA, AtrR, CBC, HapX, and NCT in Aspergillus fumigatus, and elucidate the distinctive roles of Upc2, Adr1, and Rpn4 in Candida species. Importantly, we summarize recent discoveries on the CprA-dependent regulation of Cyp51A/Erg11p and heme-mediated stability control. Based on these findings, we propose innovative antifungal strategies, including dual-target inhibition and multi-enzyme inhibition by natural products, which provide novel insights and potential directions for the development of next-generation antifungal therapies. Full article

Ferrochelatase is the terminal enzyme in heme biosynthesis. Bacillus thuringiensis (Bt) 97-27 contains two ferrochelatases, HemH1 and HemH2, but their regulatory mechanisms and functional differences under virous environmental stimuli remain unclear. This study confirmed that the iron uptake regulator protein (Fur) bound to the promoters of hemH1 and hemH2, with Fe²⁺ or Fe³⁺ enhancing this binding. Heterologous expression of HemH1 and HemH2 in Escherichia coli showed that pEH2/BL grew better than pEH1/BL under different 2,2′-Bipyridyl, Fe²⁺, and Fe³⁺ concentrations. Under iron limitation, the heme precursor ALA production decreased significantly in both strains. The heme production of pEH2/BL decreased sharply under iron-limited conditions, while that of pEH1/BL decreased significantly under iron-rich conditions. The H₂O₂ sensitivity experiment revealed that E. coli pEH1/BL was more tolerant to H₂O₂ than pEH2/BL. In Bt, ΔhemH2 was most sensitive to H₂O₂ stress, but complementation of hemH1 or hemH2 partially restored H₂O₂ resistance, with the overexpressed strain pHH2/Bt being most tolerant. β-galactosidase assays indicated that Fur positively regulated hemH1 and negatively regulated hemH2 under normal conditions, but this regulation reversed with 2.5 mM Fe³⁺. qRT-PCR showed upregulation of genes related to heme synthesis, oxidative stress, and ferrous iron transport. This study reveals the functional differentiation of HemH1 and HemH2 under the joint regulation of Fur and environmental factors, highlighting their synergistic roles in heme synthesis, heavy metal detoxification, and oxidative stress resistance to maintain bacterial physiological homeostasis. Full article

Background: Heme is an important cofactor and plays crucial roles in the correct folding of hemoproteins. The synthesis of heme can be enhanced by the plasmid-based expression of heme biosynthetic genes. However, plasmid-based expression is genetically unstable and requires the utilization of antibiotics to maintain high copy numbers of plasmids. Methods: The rate-limiting steps in heme biosynthesis were first analyzed based on previous studies and the accumulation of heme intermediates was achieved by adding heme precursor (5-aminolevulinic acid, ALA). Next, the intracellular accumulation of porphyrin was increased by deleting the porphyrin transporter TolC. Finally, the heme synthetic genes were modified by integrating the hemA and hemL genes into the cheW and yciQ locus, assembling the rate-limiting enzymes HemC and HemD with RIAD-RIDD tags, replacing the promoters of hemE/hemH genes with the constitutive promoter P_J23100, and deleting the heme degradation gene yfeX. Results: An enhanced heme supply HEME2 strain was obtained with a heme titer of 0.14 mg/L, which was 4.60-fold higher than that of the C41(DE3) strain. The HEME2 strain was applied to produce human hemoglobin and leghemoglobin. The titer and peroxidase activity of human hemoglobin were 1.29-fold and 42.4% higher in the HEME2-hHb strain than the values in the control strain C41-hHb. In addition, the peroxidase activity and heme content of leghemoglobin were increased by 39.2% and 53.4% in the HEME2-sHb strain compared to the values in the control strain C41-sHb. Conclusions: A plasmid-free Escherichia coli C41(DE3) strain capable of efficient and stable heme supply was constructed and can be used for the production of high-active hemoglobins. Full article

Background: Acute hepatic porphyrias (AHPs) represent inherited metabolic disorders of the heme biosynthesis pathway, leading to neurological and systemic impairment. Despite the presence of well-recognized chronic symptoms and signs, acute neurological, both neuromuscular and central neurological complications pose a significant challenge in clinical practice, with a potential risk of greater severity and mortality during acute decompensation episodes of AHPs. Care related to the prescription of medications, considering the risk of porphyrinogenicity, is a major and recurring concern in the acute and chronic management of AHP patients. Infectious clinical complications are significant issues in both outpatient and hospital settings for patients with AHPs. It is crucial to identify therapeutic regimens with the best safety and efficacy profiles for treating such infectious complications in AHP patients. The scarcity of structured knowledge available in guidelines and recommendations often leads to the use of therapeutic options with higher potential risks in treating patients with AHPs. Objectives: This review article aims to provide practical recommendations for managing the most significant infectious complications in clinical practice, with a focus on their impact on the clinical care of patients with AHPs. Full article