5-aminolevulinic Acid Research Articles

5-Aminolevulinic Acid Photodynamic Therapy Modulates Lipid Production by Akt/JunD-mediated NR4A1 Activation in the Treatment of Acne Vulgaris.

Severe acne vulgaris is a prevalent chronic inflammatory skin condition affecting individuals worldwide, with abnormal sebaceous gland function closely linked to its pathogenesis. 5-Aminolevulinic acid photodynamic therapy (ALA-PDT) effectively and safely treats severe acne; however, the mechanisms underlying its effects remain unclear. In this study, we first noted a decrease in lipid production following ALA-PDT in patients with clinical acne, acne-like mouse models, and the human immortalized sebocyte cell line XL-i-20. Through RNA sequencing, we identified significant upregulation of the transcription factor nuclear receptor 4A1(NR4A1) after ALA-PDT. Further confirmation of NR4A1 upregulation and its nuclear translocation under ALA-PDT was obtained in vitro and in vivo. Both the knockdown and overexpression of NR4A1 were shown to reverse or enhance the suppressive effect of ALA-PDT on lipid production. Following findings suggest that ALA-PDT inhibits the Akt signaling pathway, resulting in the activation of JunD, which subsequently enhances NR4A1 transcription and facilitates its inhibitory effect on lipid production. Overall, our findings highlight the crucial role of NR4A1 in regulating sebaceous lipids, elucidate the mechanism by which ALA-PDT treats acne, and lay the groundwork for enhancing the clinical applications of ALA-PDT.

Cancer stem cell populations are resistant to 5-aminolevulinic acid-photodynamic therapy (5-ALA-PDT)

Photodynamic therapy (PDT) is a minimally invasive treatment approved for many types of cancers. PDT involves the administration of photoactive substances called photosensitizers (PS) that selectively accumulate in cancer cells and are subsequently excited/activated by irradiation with light at wavelengths of optimal absorbance. Activated PS leads to the generation of singlet oxygen and other reactive oxygen species (ROS), promoting cancer cell death. 5-aminolevulinic acid (5-ALA) is a naturally occurring PS precursor, which is metabolically converted to the PS, protoporphyrin IX (PPIX). Although 5-ALA-PDT is effective at killing cancer cells, in prior studies conducted by our group we normally observed in in vitro experiments that approximately 5–10% of cells survive 5-ALA-PDT, which served as an impetus for further investigation. Identifying the mechanisms of resistance to 5-ALA-PDT-mediated cell death is important to prevent tumor recurrence following 5-ALA-PDT. Previously, we reported that oncogenic activation of Ras/MEK promotes PPIX efflux and reduces cellular sensitivity to 5-ALA-PDT through increased expression of ABCB1 transporter. As cancer stem cells (CSCs) are known to drive resistance to other cancer treatments and have high efflux of chemotherapeutic agents via ABC-family transporters, we hypothesize that CSCs underlie 5-ALA-PDT resistance. In this study, we determined (1) if CSCs are resistant to 5-ALA-PDT and (2) if CSCs play roles in establishing resistant populations of 5-ALA-PDT. When we compared CSC populations before and after 5-ALA-PDT, we found that CSCs were less susceptible to 5-ALA-PDT. Moreover, we found that the CSC population was enriched in 5-ALA-PDT-resistant cell lines compared to the parental cell line. Our results indicate that CSCs are not sensitive to 5-ALA-PDT, which may contribute to establishment of 5-ALA-PDT resistance.

Protective mechanisms of exogenous melatonin on chlorophyll metabolism and photosynthesis in tomato seedlings under heat stress

Elevated temperatures severely affect plant growth, reducing yield and quality. Melatonin (MT), a plant biomolecule, is known to enhance stress tolerance, but its role in heat resistance and underlying mechanisms require further exploration. This study investigates MT’s regulatory effects on chlorophyll metabolism and photosynthesis in tomato seedlings under high-temperature stress (40°C). Tomato seedlings treated with 100 μmol MT showed improved physiological and photosynthetic performance under heat stress. MT application increased osmolytes (proline and soluble sugar), enhanced antioxidant enzyme activities [catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX)], and reduced oxidative damage markers (H2O2, O2−, malondialdehyde, and conductivity). Photosynthetic parameters, including key enzyme activities [sedoheptulose-1,7-bisphosphatase (SBPase), ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), and NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (NADP-GAPDH)], photochemical efficiency [Fv/Fm and Y(II)], and photochemical quenching (Qp), were significantly improved, restoring the OJIP curve and enhancing photosynthesis. MT also regulated chlorophyll metabolism by promoting synthesis [increasing chlorophyll a and b, 5-aminolevulinic acid (ALA), Mg-protoporphyrin (Mg Proto), and protochlorophyllide (Pchlide) levels] and upregulating synthesis genes (SlHEMA1, SlPORB, SlPORC, and SlCHLI) while inhibiting degradation genes (SlCLH1, SlCLH2, SlPAO, SlPPH, and SlRCCR). These findings demonstrate that MT enhances tomato heat tolerance by protecting chlorophyll metabolism and photosynthesis, offering a theoretical basis for improving crop resilience to heat stress.

Mechanistic insights into 5-aminolevulinic acid photodynamic therapy for acne vulgaris: targeting lipogenesis via the OLR1-Wnt/β-catenin pathway

Acne vulgaris, a prevalent chronic inflammatory skin disorder, is often characterized by hyperactive sebaceous glands and excessive sebum production, presenting a significant therapeutic challenge. While 5-aminolevulinic acid photodynamic therapy (ALA-PDT) is clinically effective in treating moderate to severe acne, the molecular mechanisms underlying its therapeutic effects remain largely unexplored. In this study, we investigated the impact of ALA-PDT on lipid metabolism in an acne-like mouse model and in immortalized human sebocytes (XL-i-20), focusing on the role of the OLR1-Wnt/β-catenin pathway. We employed transcriptomic analysis, lipid staining, and gene silencing techniques to dissect the molecular interactions induced by ALA-PDT. Our findings revealed that ALA-PDT significantly reduces lipogenesis by upregulating OLR1, which in turn suppresses the SREBP1-FAS axis, thereby decreasing lipid accumulation in sebocytes. Furthermore, activation of the OLR1-Wnt/β-catenin pathway was essential for these lipogenic effects, as silencing OLR1 or activating Wnt/β-catenin signaling reversed lipogenesis inhibition. This study elucidates a novel mechanistic pathway in ALA-PDT-mediated acne treatment, highlighting OLR1 as a promising target for future therapeutic strategies.

Sonodynamic therapy with a single neoadjuvant, diffuse delivery of low-intensity ultrasound with 5-ALA in treatment naïve glioblastoma results in tumor-specific cytotoxic edema and increased apoptosis.

Sonodynamic therapy, which combines a tumor cell-selective sonosensitizer with ultrasound, is gaining attention as a promising new treatment approach for glioblastoma. The objective of this case study is to report on the first applications of 5-aminolevulinic acid (5-ALA) in combination with low-intensity, non-targeted ultrasound as neo-adjuvant treatment in therapy naïve glioblastoma. Three patients with therapy naïve newly diagnosed glioblastoma were treated once before cytoreductive surgery with 5-ALA in combination with hemispheric, low-intensity, non-targeted ultrasound, assuming cell death to be triggered by non-ablative activation of 5-ALA-induced, tumor selective porphyrins. No adverse effects were noted. Post-procedural MRI indicated a decrease in apparent diffusion coefficient values in tumors, suggesting cytotoxic effects. Relative cerebral blood volumes and leakage were increased for two patients with available perfusion imaging. Tissue obtained during surgery suggested increased cleaved-caspase III expression, a marker of apoptosis. We saw an immediate marked imaging response indicating cytotoxic edema and indications of a histopathology response from just a single treatment. Correlation to clinical outcomes and extension of overall survival remains to be seen. A Phase 1 safety study has been submitted for regulatory approval.

5-Aminolevulinic acid activates the MdWRKY71-MdMADS1 module to enhance anthocyanin biosynthesis in apple

5-Aminolevulinic acid (ALA), as a natural plant growth regulator, is well known for promoting red fruit coloring by enhancing anthocyanin accumulation. However, the underlying mechanisms remain elusive. In this study, we firstly demonstrated that ALA upregulates gene expression of the transcription factor MdMADS1, which in turn directly binds to and activates transcription of the key anthocyanin biosynthetic genes, MdCHS and MdUFGT. Then, we identified a novel WRKY transcription factor, MdWRKY71, that interacts with MdMADS1. Through gene manipulation, we revealed that MdWRKY71 plays a pivotal role in ALA-induced anthocyanin accumulation, highlighting its regulatory significance in this process. Further investigation unveiled that MdWRKY71 not only activates MdMADS1 transcription but also enhances its transcriptional activation on its target genes, MdCHS and MdUFGT. Additionally, we discovered that MdWRKY71 independently binds to and activates the transcription of two other anthocyanin biosynthetic genes, MdANS and MdDFR. The protein–protein interaction between MdWRKY71 and MdMADS1 amplifies the transcriptional activation of these genes by MdWRKY71. These findings delineate a fine and complex regulatory framework where MdWRKY71 and MdMADS1 coordinately regulate anthocyanin biosynthesis in apples, providing new insights into the molecular control of fruit coloration and offering potential target genes for breeding aimed at enhancing fruit quality.

A novel acquired resistance mechanism to 5-aminolevulinic acid-mediated photodynamic therapy with ABCG2 inhibition.

We report the occurrence of acquired tumor cell resistance to 5-aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) in combination with ABCG2 inhibition. ALA-PDT in combination with either an ABCG2 tool inhibitor Ko143 or a repurposed clinically-relevant ABCG2 inhibitor lapatinib was highly effective in eradicating the H4 human glioma cells, resulting in minimal cell survival after treatment. However, after seven rounds of repeated treatments with light dose escalation, the resultant tumor cells became resistant to the combination therapy. The resistant sublines and the parental cell line showed similar ABCG2 activities and protein levels, indicating that it was not ABCG2 that caused the resistance. They also exhibited similar responses to PpIX-PDT and mTOR inhibitor AZD2014, suggesting that alterations in PDT sensitivity and mTOR pathway had little contribution to the development of resistance phenotype. By determining the intracellular and extracellular PpIX levels, the activities and protein levels of heme biosynthesis enzymes, we found that porphobilinogen deaminase (PBGD) activity and protein level were significantly reduced in the resistant sublines, causing resistance to PDT by substantially reducing PpIX biosynthesis. A novel acquired resistance mechanism to ALA-PDT with ABCG2 inhibition has been uncovered.

Application of Photodynamic Therapy with 5-Aminolevulinic Acid and Fractional CO2 Laser for the Management of Recalcitrant Plantar Warts

Plantar warts, benign lesions on the soles of the feet, are caused by the human papillomavirus (HPV) infecting keratinocytes. Complete eradication of these warts is challenging, often leading to recurrences. This study evaluates the combined clinical efficacy of topical 5-aminolevulinic acid (5-ALA) photodynamic therapy (PDT) and fractional carbon dioxide (CO2) laser treatment for recalcitrant plantar warts. Data from 10 patients with recalcitrant plantar warts were analyzed. Initially, thickened hyperkeratotic tissue was removed using a super-pulsed CO2 laser. This was followed by fractional laser application, after which a 20 % 5-ALA cream was applied occlusively for 4 h. Patients then received He-Ne laser irradiation for 30 min at an energy density of 100 mW/cm², with treatments spaced 4 weeks apart. The study included 10 participants aged 24 to 53 years (mean age: 33.4 ± 8.09 years). In total, 40 lesions were treated across 1 to 9 PDT sessions, with an average of 5.2 ± 2.86 sessions per patient. Complete clearance was achieved in 3 patients (30 %), 4 patients (40 %) showed an excellent response (≥80 % improvement), while 2 patients had a partial response. One patient (10 %) showed <50 % improvement. The overall clearance rate was 70 % (28 out of 40 lesions). Aside from temporary pain during the procedure and mild erythema post-treatment, one patient developed localized proliferative scarring. After a one-year follow-up, only one patient experienced recurrence. The combination of 5-ALA PDT and fractional CO2 laser therapy shows promise as an effective and safe alternative for treating persistent plantar warts.

Survival Analysis of Glioblastoma: A Scientometric Perspective

Glioblastoma is the most aggressive primary brain tumor and the outlook for patients is usually pessimistic. Numerous ongoing studies have focused on enhancing the survival rate of glioblastoma patients. This study aims to analyze the research trends surrounding glioblastoma survival and facilitate studying recent topics to provide insight into the perspective, research fields, and international collaborations. Data were collected from the Web of Science database documents published from 1980 to 2022 and analyzed using Citespace and Biblioshiny software. After analyzing the data, we visualized the co-occurrence and coauthorship networks. Eighteen main clusters were formed by drawing a document cocitation network. The result indicates that prognostic biomarkers, treating field, T cell, radiomic feature, and 5-aminolevulinic acid were trending topics for researchers. The most active countries in this field are the United States, followed by China, Germany, and Italy, respectively. Considering the significance of monitoring the studies in glioblastoma patients, the current research has shown promising results in stratifying patient survival as a valuable tool for prognosis and prediction and eventually guiding treatment decisions. Using the results of this study, glioblastoma researchers can identify their potential colleagues and research gaps in this field.

Long-term outcome of photodynamic therapy with hexyl aminolevulinate, 5-aminolevulinic acid nanoemulsion and methyl aminolevulinate for low-risk Basal Cell Carcinomas

Non-surgical treatments are cost-effective options for low-risk basal cell carcinomas (BCCs) i.e. superficial or small nodular BCCs located outside the high-risk locations. Hexyl aminolevulinate (HAL) and 5-aminolevulinic acid nanoemulsion (BF-200 ALA) with enhanced penetration depth enables the use of lower concentrations compared to methylaminolevulinate (MAL) in photodynamic therapy (PDT). We have previously reported comparable short-term efficacies for MAL 16 %, BF-200 ALA 7.8 % and HAL 2 % in PDT of low-risk BCC, and here we report the long-term results. The goal of this trial was to compare long-term outcomes of HAL and BF-200 ALA, compared to MAL in PDT of low-risk BCCs. Ninety-eight histologically verified low-risk BCCs on the trunk or extremities were included and randomized into three arms to receive PDT in two sessions with MAL, BF-200 ALA or HAL. A blinded dermatologist assessed the response, cosmetic outcome, and obtained biopsies for histological verification at three months, one year and five years. Histologically verified non-responsive lesions were excised. Patients' satisfaction with the treatment was also queried. According to intention-to-treat (ITT) analyses, the cumulative response rate at one year was 90.6 % for MAL, 81.3 % for BF-200 ALA, and 75.8 % for HAL, and correspondingly at five years 71.9 %, 54.6 % and 60.6 %. There were no statistically significant differences between interventions and comparator. The overall cumulative response rate for PDT was 82.5 % at one year and 62.2 % at five, and 48.6 % of the treatment failures were recorded at five years. The recurrent lesions were excised as second line treatment. No aggressive subtypes were reported, with only superficial or nodular growth in the final histopathological report. There were no significant differences in cosmetic outcome or patient satisfaction. This trial shows that HAL has potential for dermatological PDT. However, the long-term efficacy of PDT in the treatment of low-risk BCCs remains rather low.

Efficacy and safety of 5-aminolevulinic acid photodynamic therapy in refractory genital lichen sclerosus

Genital lichen sclerosus (GLS) is a chronic inflammatory skin disease affecting the genital and anal areas. Treatment of refractory remains a challenge in clinical practice. This study aimed to evaluate the efficacy and safety of 5-aminolevulinic acid photodynamic therapy (5-ALA PDT) for refractory GLS. Thirty-five patients with histopathologically confirmed GLS (including 32 females and 3 males) were treated with 5-ALA PDT. Lesion pretreatment was performed to enhance photosensitizer penetration, and fluorescence diagnosis was used for precise point-to-point treatment. Efficacy and safety were systematically evaluated by assessing treatment outcomes, symptom improvement, side effects and maintenance of efficacy over a 6-month follow-up period. After treatment, most patients experienced significant relief of pruritus, improved skin elasticity and color, and reduced lesion area. After 6 treatment sessions, 11 patients (31.43 %) achieved complete resolution of pruritus, with 3 patients (8.57 %) achieving complete remission after 3 sessions. Cattaneo scores decreased significantly after treatment and during follow-up (P < 0.05). Adverse reactions were mainly mild pain, which could be relieved by ice compression or oral analgesics. 5-ALA PDT shows significant efficacy and good safety for refractory GLS, improving the clinical symptoms and signs of patients, and warrants wider clinical application.

Effects of ALA-PDT on the murine footpad model of Fonsecaea monophora infection and its related mechanisms in vivo.

5-aminolevulinic acid photodynamic therapy (ALA-PDT) has received growing attention for treating chromoblastomycosis (CBM) and has shown efficacy in a handful of clinical case reports. However, there is insufficient information regarding the effects of ALA-PDT on Fonsecaea monophora in mouse infection model and the related mechanisms. This study investigated these issues in vivo. A F. monophora infection mouse model inoculated in footpads was used. Changes in the footpad volume, tissue fungal burden, and histopathological characteristics were investigated to determine the efficacy of ALA-PDT. Scavenger receptor MARCO (Macrophage receptor with collagenous structure) was further evaluated at the gene and protein levels. Serum cytokines TNF-α, GM-CSF, IL-4, and IL-10 were measured using enzyme-linked immunosorbent assay to indicate changes in the immune microenvironment after PDT. ALA-PDT reduced infected footpad volume, fungal burden, and pathological inflammatory infiltration in vivo. It also increased the expression of Marco in the murine infection model. Furthermore, PDT upregulated the anti-inflammatory cytokines IL-4 and IL-10 while downregulated the pro-inflammatory cytokines TNF-α and GM-CSF in mouse serum. ALA-PDT demonstrated fungicidal effects in a mouse footpad infection model with F. monophora and attenuated the inflammatory reactions. It may also assist against the intracellular fungi by the host through macrophage receptor MARCO and regulation of the immune microenvironment. This study provides scientific evidence for the protocol selection of ALA-PDT as a promising adjunctive modality for treating chromoblastomycosis.

Topical riboflavin versus 5-aminolevulinic acid photodynamic therapy for the treatment of mild to moderate acne: A split-face randomized study.

ALA-PDT has been widely used in mild to moderate acne vulgaris worldwide. However, very few studies used riboflavin-PDT to treat acne vulgaris. To investigate the efficacy and adverse events of riboflavin-PDT to treat mild to moderate facial acne, and compare it with ALA-PDT on a non-inferiority basis. 33 eligible patients were enrolled, and 30 patients completed follow-up. Either side of the face was assigned randomly to riboflavin or ALA blue-light-PDT. Patients received 3 sessions of PDT in 1-week intervals and were followed up at weeks 4, 6, and 10. Both ALA and riboflavin-PDT significantly reduced non-inflammatory and inflammatory lesions at weeks 4, 6, and 10 compared to baseline (P all <0.001). For the primary outcome, the difference in the improvement rate of total lesions between the Ribo and ALA side was 2.6 % (-4.3 %, 12.5 %; p = 0.71), which didn't reach the inferiority margin. Patients described greater in-treatment pain and burning sensation (P < 0.001), more prominent post-treatment erythema (P = 0.003), hyperpigmentation (P < 0.001), and desquamation (P = 0.006) on the ALA side than on riboflavin side. The efficacy of riboflavin-PDT was comparable to that of blue-light ALA-PDT in treating mild to moderate acne vulgaris. Riboflavin-PDT had fewer in-treatment and post-treatment adverse events than ALA-PDT.

5-aminolevulinic acid in photodynamic therapy used in dermatology as a method of treating acne vulgaris.

Acne therapy is a difficult task and the number of patients struggling with the disease is increasing, but new treatment options are emerging. One such indication is precisely the use of 5-aminolevulinic acid in photodynamic therapy for the treatment of acne lesions. The given issue has been widely discussed on the basis of a number of research papers from around the world, whose publications have promising results. The results of the studies show the effectiveness of using ALA-PTD terpy in the treatment of acne lesions occurring in acne vulgaris. Photodynamic therapy with 5-ALA acid may also serve as a good complementary treatment to other substances. However, studies need to be conducted to obtain data to develop procedures to achieve the most effective results, with the development of minimal side effects, which include pruritus, redness, transient hyperpigmentation coming off without leaving a scar and the occurrence of allergic reactions

Alleviation of cadmium toxicity by improving antioxidant defense mechanism and photosyntetic pigments in Clitoria fairchildiana R.A Howard seedlings through foliar application of 5-ALA

The objective of this work was to evaluate the biometric parameters, photosynthetic pigments and the antioxidant system of Clitoria fairchildiana R.A Howard seedlings subjected to exogenous application of 5-aminolevulinic acid and different concentrations of cadmium (Cd). The experiment was conducted in a greenhouse from May to August 2023. Initially, seedlings were produced from straw seeds. After three months, they were transplanted into 3 kg pots containing previously corrected and fertilized black soil. Ten days after transplanting, the plants received exogenous application of 5-ALA, weekly for 5 weeks, totaling 5 applications. After three days of acclimatization, cadmium concentrations were applied in a single time (42nd DAT), in the form of Cadmium Chloride (CdCl2.H2O): 0 (Control), 15 and 30 mg/L-1. The experimental design was completely randomized blocks (CRB), in a 3x3 factorial scheme, specified as follows: three concentrations of Cd (0, 15 and 30 mg L-1 of CdCl2.H20); and three concentrations of 5-ALA (0, 50 and 100 mg L-1 5-ALA), with 9 replicates. The main biometric and photosynthetic pigment variables showed changes with the application of 5-ALA and little variation in the levels subjected to the presence of cadmium. For the antioxidant system, the activity of the enzymes guaiacol peroxidase (G-POD), ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) suffered oscillations in their levels due to the application of 5-ALA and Cd, varying according to the concentration of the metal and the part of the plant.

Safety of Oral Administration of 5-Aminolevulinic Acid Phosphate Combined with Ferrous Iron in Healthy Subjects: An Open-Label Trial

The combination of 5-aminolevulinic acid (5-ALA) phosphate and sodium ferrous citrate (SFC) has been approved as an ingredient in dietary supplements in several countries, owing to its broad applicability in healthcare. This study aimed to assess the safety of oral administration of 5-ALA and SFC in healthy adults at doses several times higher than those commercially available. This study included 22 healthy subjects (11 males and 11 females) aged 21–59. Doses of 250 mg 5-ALA phosphate and 143.4 mg SFC (15 mg Fe) per day were administered orally for 28 days. Blood tests, urinalysis, and medical interviews were performed to assess safety. No test compound-related adverse events or abnormal changes were observed, except for elevated serum Fe levels, which were mild-to-moderate and transient. In conclusion, the combined oral administration of 5-ALA phosphate and SFC in healthy adults was safe and well-tolerated at the dose and duration investigated in this study.

Boosting porphyrin synthesis and ALA-mediated photoinactivation through near-infrared therapy.

Photodynamic inactivation (PDI) combines the use of photosensitizers with visible light to produce reactive oxygen species that effectively eliminate pathogens. To investigate the impact of near- infrared therapy (NIRT) on heme biosynthesis and permeability of the pro-photosensitizers 5-aminolevulinic acid (ALA) and Hexyl-ALA (H-ALA) through biofilms, we applied sub-lethal conditions for both NIRT and PDI to maintain intact bacterial viability. During NIRT, the temperature remained below 37°C, permitting rapid heating (ΔT = 11°C) without causing thermal damage. NIRT potentiated the bactericidal effects of ALA-PDI by 3 logs in Staphylococcus aureus RN6390 biofilms and 4 logs in ST5-SCCmecI biofilms. With H-ALA-PDI, reductions of 4 and 6 logs, respectively, were observed. In the case of ALA, this enhancement was partly due to increased porphyrin synthesis, a result not replicated by simple heating. For H-ALA, the enhanced effect of PDI was likely due to biofilm or bacterial membrane destabilization caused by NIRT and H-ALA. Unlike biofilms, applying the same ALA-PDI conditions, the treatment was effective in planktonic S. aureus RN6390 cultures, reducing the bacteria by 3 logs, with no additional benefit from NIRT, suggesting that NIRT primarily aids in penetrating the biofilm matrix rather than the bacterial cells. Confocal fluorescence microscopy confirmed that NIRT-treated biofilms exposed to ALA exhibited higher porphyrin fluorescence than untreated biofilms. These findings support the use of NIRT in enhancing the effectiveness of PDI against bacterial biofilms.

Photodynamic Therapy with Protoporphyrin IX Precursors Using Artificial Daylight Improves Skin Antisepsis for Orthopedic Surgeries.

Classical preoperative skin antisepsis is insufficient in completely eliminating bacterial skin colonization for arthroplasty. In contrast, photodynamic therapy (PDT) with red light and methyl-aminolevulinate (MAL), combined with skin antisepsis, led to the absence of bacterial growth in healthy participants, though with local skin erythema, posing an obstacle for orthopedic surgery. Therefore, we explored whether artificial daylight PDT (PDT-DL) was superior to red light. Twenty healthy participants were allocated to either 5-aminolevulinic acid-(5-ALA) PDT-DL (n = 10) or MAL-PDT-DL (n = 10) before antisepsis with povidone-iodine/alcohol. Skin swabs from the groin were taken to cultivate bacteria at baseline, after PDT-DL, and after the subsequent antisepsis. Additional swabs were taken on day 4 before and after antisepsis without PDT. The contralateral groin of each participant and of ten additional healthy volunteers served as the control (n = 30). In selected participants, 16S rRNA-based amplicon deep sequencing was performed. All participants showed a baseline bacterial colonization. After a PDT-DL with skin antisepsis, bacterial growth occurred in three (30%) and in one (10%) participants with 5-ALA and MAL, respectively, compared to the sixteen (55%) participants in the control group. On day 4, three (30%) participants per group showed positive cultures post antisepsis. Adverse effects were reported in six (60%) and zero (0%) participants for 5-ALA- and MAL-PDT-DL, respectively. The skin bacteriome changes correlated with the bacterial culture results. The MAL-PDT-DL with skin antisepsis significantly increased bacterial reduction on the skin without adverse effects. This offers an opportunity to prevent infections in arthroplasty patients and reduce antibiotic use, thus contributing to antibiotic stewardship goals emphasized in the One Health approach.

Metabolic engineering of Escherichia coli for enhanced production of p-coumaric acid via L-phenylalanine biosynthesis pathway.

p-Coumaric acid (p-CA), an invaluable phytochemical, has novel bioactivities, including antiproliferative, anxiolytic, and neuroprotective effects, and is the main precursor of various flavonoids, such as caffeic acid, naringenin, and resveratrol. Herein, we report the engineering of Escherichia coli for de novo production of p-CA via the PAL-C4H pathway. As the base strain, we used the E. coli H-02 strain, which was previously engineered for sufficient supplementation of L-phenylalanine, the main precursor of p-CA. For the bioconversion of L-Phe to p-CA, we constructed and optimized an expression system for phenylalanine ammonia lyase (SmPAL), codon-optimized cinnamate 4-hydroxylase (AtC4H), and its redox partner, cytochrome P450 reductase (AtCPR1). We confirmed that the engineered cell showed higher production of p-CA at 30°C and the addition of 0.5mM 5-aminolevulinic acid could increase the production titer further. Subsequently, the main pathways of acetic acid (poxB and pta-ackA) were eliminated to reduce its accumulation and restore cell growth. Next, to increase the available pool of cofactor (NADPH), the co-expression system of the zwf gene in the pentose phosphate pathway (PPP) was integrated into genome and the expression level was optimized with synthetic promoters. Finally, by optimizing fed-batch culture in a 5 L-scale bioreactor, the engineered strain achieved 1.5g/L p-CA with a productivity of 31.8mg/L/h.

Analysis of the Transcriptome Provides Insights into the Photosynthate of Maize Response to Salt Stress by 5-Aminolevulinic Acid.

Salt stress is a significant environmental factor that impedes maize growth and yield. Exogenous 5-aminolevulinic acid (ALA) has been shown to mitigate the detrimental effects of various environmental stresses on plants. However, its regulatory role in the photosynthesis mechanisms of maize seedlings under salt stress remains poorly understood. Transcriptome sequencing and physiological index measurements were conducted on the leaves of the "Zhengdan 958" cultivar subjected to three different treatments. Differential expression analysis revealed 4634 differentially expressed genes (DEGs), including key transcription factor (TF) families such as NAC, MYB, WRKY, and MYB-related, across two comparisons (SS_vs_CK and ALA_SS_vs_SS). Significant enrichment was observed in the metabolic pathways related to porphyrin metabolism, photosynthesis-antenna proteins, photosynthesis, and carbon fixation in photosynthetic organisms. ALA treatment modulated the expression of photosynthesis-related genes, increased photosynthetic pigment content, and enhanced the activities of superoxide dismutase (SOD) and catalase (CAT), thereby mitigating the excessive accumulation of reactive oxygen species (ROS). Furthermore, ALA increased starch content under salt stress. These findings establish a foundational understanding of the molecular mechanisms through which ALA regulates photosynthesis under salt stress in maize seedlings. Collectively, exogenous ALA enhances maize's salt tolerance by regulating photosynthesis-related pathways.