Search Results (129)

Agronomic biofortification offers an environmentally friendly way to improve crop nutrition. The biofortification of vegetables with iodine has attracted increasing attention due to its significance for human health. Hydrogen sulphide (H₂S) is a gaseous signalling molecule that affects many physiological and biochemical processes in plants. Lettuce (Lactuca sativa L.) plants were cultivated under controlled greenhouse conditions. Foliar applications of potassium iodate (KIO₃) and hydrogen sulphide (H₂S, supplied by sodium hydrosulphide (NaHS)) were applied separately and together (H₂S + KIO₃). Evaluations included growth parameters, photosynthetic pigments, biochemical metabolites, antioxidant enzyme activities, plant hormone levels, and mineral nutrient contents. All treatments resulted in significant changes in plant growth and physiological traits compared to the control. The combined application resulted in greater responses across several parameters; however, these observations do not demonstrate a causal or mechanistic interaction between the treatments. The combined application increased plant fresh weight by ~42% and leaf area by ~35% compared to the control. Total chlorophyll content approximately doubled (≈100% increase), while SOD, POD, and CAT activities increased by up to ~160%, ~13%, and ~40%, respectively. Proline and sucrose contents increased by approximately 100% and 85%. Hormonal changes included increases in indole-3-acetic acid (~44%) and cytokinins (~55%), and a decrease in abscisic acid (~20%). In addition, several macro- and micronutrients in leaves and roots were affected by the treatments. The combined application of KIO₃ and H₂S was associated with greater responses across several measured parameters than either compound alone; however, these observations do not demonstrate a causal or mechanistic interaction between the two compounds. Furthermore, as the experiment was conducted under non-stress greenhouse conditions, the observed physiological responses should be interpreted as changes in metabolic and regulatory processes rather than direct evidence of enhanced stress tolerance. Overall, the results indicate that foliar application of KIO₃ and H₂S can influence growth and physiological traits of lettuce under controlled conditions. Full article

Chronic diabetic wounds are challenging to treat due to persistent inflammation, oxidative stress, impaired angiogenesis, and dysregulated matrix remodelling. Hydrogen sulphide (H₂S) has emerged as a therapeutic mediator with antioxidant, anti-inflammatory, and pro-angiogenic properties; however, its clinical translation is limited by volatility and a short biological half-life. Controlled delivery systems, such as hydrogels, are therefore required to harness its potential. This study aimed to develop and evaluate a sodium 2-acrylamido-2-methylpropane sulfonate (Na-AMPS)-based adhesive hydrogel incorporating AP39, a mitochondria-targeted H₂S donor, for sustained localised delivery and promotion of wound healing. Hydrogel formulations were characterised for rheological behaviour, adhesion, swelling, and AP39 release. Cytocompatibility was assessed in human umbilical vein endothelial cells (HUVECs); human dermal fibroblasts, adult (HDFa); and keratinocytes. Anti-inflammatory, antioxidant, and matrix-modulatory effects were evaluated via interleukin-6 and 8 (IL-6/IL-8) secretion, reactive oxygen species (ROS) levels, mitochondrial membrane potential, matrix metalloproteinase-9 (MMP-9), and transforming growth factor-beta (TGF-β). Functional wound healing activity was assessed using tube formation and scratch assays in endothelial cells. AP39-loaded hydrogels exhibited predominantly elastic, shear-thinning behaviour, strong adhesion, rapid hydration, and sustained release of AP39 (11.63 ± 1.20% over 24 h). Across all cell types, 500 nM concentrations of AP39 were well tolerated. In diabetic-like stress conditions, AP39 significantly decreased ROS in HUVECs (50122 ± 5999 to 33,087 ± 1865 AU; p < 0.0001) and HDFa cells (41,367 ± 4225 to 29,813 ± 2406 AU; p < 0.0001). AP39 improved mitochondrial membrane potential in both cell types (p < 0.01–0.001) and decreased pro-inflammatory cytokines. IL-6 decreased in HUVECs (96.05 ± 4.22 pg/mL to 60.99 ± 4.21 pg/mL; p < 0.0001) and HDFa cells (77.54 ± 8.94 pg/mL to 52.25 ± 6.78 pg/mL; p < 0.001), whilst in HDFa cells, MMP-9 was reduced (419.4 ± 25.51 pg/mL to 174 ± 15.1 pg/mL; p < 0.0001). Finally, wound closure was enhanced in HUVECs. The AP39-loaded Na-AMPS hydrogel represents a multifunctional wound dressing capable of controlled H₂S delivery, mechanical stability, and biological activity to support tissue repair in diabetic wound environments. These results highlight this gel’s therapeutic potential for diabetic wound treatment. Full article

The transition to sustainable energy systems has intensified the search for renewable alternatives to reduce greenhouse gas emissions and reliance on fossil fuels. In this context, microalgae have emerged as a promising third-generation feedstock for biofuel production due to their rapid development, high lipid content, and ability to grow in wastewater without competing with freshwater resources. In this study, the hydrotreatment of biocrudes derived from C. vulgaris, T. obliquus, and a mixed microalgal culture cultivated in domestic wastewater is investigated. Catalytic upgrading was applied using sulphided CoMo/Al₂O₃ (sCoMo) and Pt/Al₂O₃ catalysts. The results demonstrated that catalytic upgrading enhanced the upgraded bio-oils’ quality compared to non-catalysed reactions, confirming the crucial role of catalysts in improving bio-oil properties. Compared with the Pt catalyst, sCoMo produced higher yields of upgraded bio-oil, greater enrichment in carbon and hydrogen, and higher heating value (HHV), while effectively enhancing nitrogen and oxygen removal. However, when compared with the non-sulphided CoMo, the sulphiding treatment did not significantly improve denitrogenation and treated oil yields. The highest fraction of components within the jet fuel boiling range (37.7%) was obtained using a Pt catalyst, while the non-catalysed process yielded the lowest (26.6%). In this sense, catalytic upgrading of microalgae-based biocrude represents an important step towards the production of advanced and environmentally sustainable fuels. Full article

Vascular inflammation and endothelial dysfunction are key drivers in the development of cardiovascular and neurovascular diseases. Mitochondrial dysfunction and oxidative stress further amplify inflammatory cascades, emphasising the need for targeted strategies that restore endothelial homeostasis at the subcellular level. Hydrogen sulphide (H₂S) donors, such as AP39, offer cytoprotective benefits but are limited by short half-life and rapid release of the active compound, H₂S. We developed poly(lactic-co-glycolic acid) (PLGA) nanoparticles encapsulating AP39 (PLGA-AP39) to achieve sustained, mitochondria-targeted H₂S delivery. Nanoparticles were characterised by size, polydispersity, zeta potential, encapsulation efficiency, and in vitro release kinetics. Human umbilical vein endothelial cells (HUVEC) were exposed to TNF-α to induce inflammation, followed by treatment with free AP39 or PLGA-AP39. Anti-inflammatory effects were assessed by measuring IL-6, IL-8, and TGF-β levels. Mitochondrial function was evaluated using a Seahorse XFe24 Analyser, membrane potential assays, and mitochondrial ROS detection. Moreover, we investigated vascular function by analysing capillary-like tube formation and wound closure in response to treatments. PLGA-AP39 nanoparticles displayed a uniform size (~227 nm), low PDI, and high encapsulation efficiency (>78%). Sustained AP39 release was observed over seven days. Treatment with PLGA-AP39 significantly restored TNF-α-induced endothelial dysfunction and reduced TNF-α-induced release of IL-6, IL-8, and TGF-β compared to untreated controls. Seahorse analysis revealed restoration of maximal respiration and increased spare respiratory capacity. Encapsulated AP39 also preserved mitochondrial membrane potential and reduced mitochondrial ROS production, demonstrating enhanced protection against inflammation-induced metabolic dysfunction. This work establishes a novel nanoparticle-based strategy for prolonged, mitochondria-specific H₂S delivery to counteract vascular inflammation and enhance endothelial bioenergetics. The results from this work are pioneering in the generation of a novel delivery method for H₂S donors employing PLGA and represent a promising therapeutic avenue for treating chronic vascular inflammatory disorders. Full article

Background: Parkinson’s disease (PD) involves progressive neurodegeneration with clinical or subclinical disturbance of the gut–brain axis, including altered gastrointestinal motility and enteric nervous system involvement. Clinical studies have reported gut microbiome alterations in PD, with shifts in taxa associated with inflammatory signalling and short-chain fatty acid (SCFA) metabolism. Photobiomodulation (PBM), a non-invasive light therapy, has been investigated as a potential adjunctive treatment for PD, with proposed effects on neural, metabolic, and immune pathways. We previously reported the five-year clinical outcomes in a PBM-treated Parkinson’s disease case series. Here we report the five-year gut microbiome outcomes based on longitudinal samples collected from the same participants. This was an exploratory, open-label longitudinal study without a control group. Objective: Our objective was to assess whether long-term PBM was associated with changes in gut microbiome diversity and composition in the same Parkinson’s disease cohort as previously assessed for changes in Parkinson’s symptoms. Methods: Six participants from the earlier PBM proof-of-concept study who had been diagnosed with idiopathic PD and who had continued treatment (transcranial light emitting diode [LED] plus abdominal and neck laser) for five years had their faecal samples analysed by 16S rDNA sequencing to assess microbiome diversity and taxonomic composition. Results: Microbiome analysis revealed significantly reduced evenness (α-diversity) and significant shifts in β-diversity over five years, as assessed by Permutational Multivariate Analysis of Variance (PERMANOVA). At the phylum level, Pseudomonadota and Methanobacteriota decreased in four of the six participants. Both of these phyla are often increased in the Parkinson’s microbiome compared with the microbiomes of healthy controls. Family-level changes included increased acetate-producing Bifidobacteriaceae (five of the six participants); decreased pro-inflammatory, lipopolysaccharide (LPS)-producing Enterobacteriaceae (two of the three participants who have this bacterial family present); and decreased LPS- and H₂S-producing Desulfovibrionaceae (five of six). At the genus level, Faecalibacterium, a key butyrate producer, increased in four of the six participants, potentially leading to more SCFA availability, although other SCFA-producing bacteria were decreased. This was accompanied by reductions in pro-inflammatory LPS and H₂S-producing genera that are often increased in the Parkinson’s microbiome. Conclusions: This five-year case series represents the longest follow-up of microbiome changes in Parkinson’s disease, although the interpretation of results is limited by very small numbers, the lack of a control group, and the inability to control for lifestyle influences such as dietary changes. While causal relationships cannot be inferred, the parallel changes in improvements in mobility and non-motor Parkinson’s symptoms observed in this cohort, raises the hypothesis that PBM may interact with the gut–brain axis via the microbiome. Controlled studies incorporating functional multi-omics are needed to clarify potential mechanistic links between microbial function, host metabolism, and clinical outcomes. Full article

Odour emissions from wastewater infrastructure represent a significant environmental and social challenge in urban areas. This study evaluates the odour impact of a municipal wastewater pumping station using an integrated field-based approach that combines sensory observations, chemical measurements and meteorological data. Field olfactometry and on-site gas monitoring were applied over a two-year campaign covering different operational and seasonal conditions. The results indicate that odour perception is strongly influenced by hydrogen sulphide concentration, air temperature and wind speed, with short-term high-intensity episodes playing a disproportionate role in odour nuisance. To support integrated interpretation, a Synthetic Odour Index (SOI) was developed to consolidate chemical, sensory and microclimatic information into a single numerical indicator, extending existing odour indices by explicitly integrating field-based sensory and meteorological data. The SOI showed a moderate but statistically significant association with odour intensity (r ≈ 0.3) and effectively differentiated low- and high-nuisance conditions. The proposed methodology demonstrates the value of combining field measurements with integrated data analysis for assessing and managing odour emissions from urban wastewater pumping stations and provides a practical basis for operational monitoring and odour mitigation strategies. Full article

Landfills are vital waste management techniques in South Africa but are significant sources of greenhouse gases (GHGs) and air pollutants that can threaten nearby communities. This study provides a novel integrated assessment approach by combining high-resolution TROPOMI satellite observations with AERMOD dispersion modelling. This study investigates the dispersion characteristics and potential health impacts of landfill gas (LFG) emissions from the Thohoyandou landfill. Unlike previous studies that rely solely on modelling or field measurements, this work offers the first satellite-validated landfill gas dispersion analysis in South Africa. The modelling results indicated that the highest hourly concentrations reached 456,056 µg/m³ for CH₄ and 735,108 µg/m³ for CO₂, while annual maximum concentrations were 15,699 µg/m³ and 30,590 µg/m³, respectively. Health risk assessments were performed for 26 volatile organic compounds and hazardous air pollutants (VOCs/HAPs) using the USEPA methodology. Most individual hazard quotient (HQ) values were below 1, except for 1,1,2-trichloroethane (HQ = 1.27). The cumulative HQ of 1.86 suggested a potential non-carcinogenic risk for nearby residents. Carcinogenic risk analysis identified 13 compounds, with hydrogen sulphide posing the highest probability of cancer risk. The findings reveal that LFG emissions may adversely affect air quality and present both non-carcinogenic and carcinogenic health risks to populations living or working near the landfill. Full article

This study presents a novel approach for the synthesis of tin(II) sulphide (SnS) by integrating ultrasonic spray pyrolysis (USP) with hydrogen reduction (HR), using tin(II) sulphate (SnSO₄) as a precursor. The method combines aerosol droplet generation using ultrasonic atomisation at 1.7 MHz with gas-phase reduction in a tube reactor under H₂-N₂ mixed gas flow. Thermochemical assessment indicated that SnS formation is thermodynamically favourable from 400 to 1000 °C, in reasonable agreement with experimental results. XRD analysis confirmed the formation of SnS as the main phase accompanied by SnO₂ as a secondary product without SnSO₄ when conducting USP-HR at 1000 °C. SEM images revealed flake-like, spherical, and agglomerated morphologies, with EDS confirming distinct Sn-S regions. This study demonstrates the feasibility of producing SnS powder using a simple precursor system and a clean reducing environment. The process offers a scalable and controllable synthesis route for SnS materials, providing an alternative to conventional substrate-based deposition techniques. Further optimisation of reaction temperature and residence time is expected to enhance phase purity and reduce agglomeration. Full article

Microorganisms such as methanogenic archaea play a key role in wastewater treatment plants (WWTPs) by breaking down organic matter and pollutants and producing methane, a potential renewable energy source. However, sulphate-reducing bacteria (SRB) compete with archaea for the same substrates under anaerobic conditions, lowering methane production and generating harmful hydrogen sulphide (H₂S). Inhibiting SRB is therefore crucial to enhance methane yield and reduce toxic by-products. By means of manual screening of public databases (KEGG, BRENDA, PDB, PubChem) 12 potential inhibitors of SRB were found. After computational ecotoxicological assessment, four candidates were selected, and one of them experimentally increased methane production, demonstrating that SRB inhibition favours the anaerobic digestion of sludges. In order to further explore new candidates, Quantitative Structure–Activity Relationship (QSAR) models were developed showing reliable predictive performance. These models enabled the virtual screening of COCONUT, a natural product database, identifying 73 potential SRB inhibitors. After an ecotoxicological assessment, five commercially available compounds remained. The identified candidates may reduce competition between SRB and methanogenic archaea, leading to higher methane production and supporting WWTPs in generating their own biogas. This would contribute to a circular economy and help mitigate greenhouse gas emissions. Full article

The growing demand for air connectivity, coupled with the forecasted increase in passengers by 2040, implies an exigency in the aviation sector to adopt sustainable approaches for net zero emission by 2050. Sustainable Aviation Fuel (SAF) is currently the most promising short-term solution; however, ensuring its overall sustainability depends on reducing the life cycle carbon footprints. A key challenge prevails in hydrogen usage as a reactant for the approved ASTM routes of SAF. The processing, conversion and refinement of feed entailing hydrodeoxygenation (HDO), decarboxylation, hydrogenation, isomerisation and hydrocracking requires substantial hydrogen input. This hydrogen is sourced either in situ or ex situ, with the supply chain encompassing renewables or non-renewables origins. Addressing this hydrogen usage and recognising the emission implications thereof has therefore become a novel research priority. Aside from the preferred adoption of renewable water electrolysis to generate hydrogen, other promising pathways encompass hydrothermal gasification, biomass gasification (with or without carbon capture) and biomethane with steam methane reforming (with or without carbon capture) owing to the lower greenhouse emissions, the convincing status of the technology readiness level and the lower acidification potential. Equally imperative are measures for reducing hydrogen demand in SAF pathways. Strategies involve identifying the appropriate catalyst (monometallic and bimetallic sulphide catalyst), increasing the catalyst life in the deoxygenation process, deploying low-cost iso-propanol (hydrogen donor), developing the aerobic fermentation of sugar to 1,4 dimethyl cyclooctane with the intermediate formation of isoprene and advancing aqueous phase reforming or single-stage hydro processing. Other supportive alternatives include implementing the catalytic and co-pyrolysis of waste oil with solid feedstocks and selecting highly saturated feedstock. Thus, future progress demands coordinated innovation and research endeavours to bolster the seamless integration of the cutting-edge hydrogen production processes with the SAF infrastructure. Rigorous techno-economic and life cycle assessments, alongside technological breakthroughs and biomass characterisation, are indispensable for ensuring scalability and sustainability. Full article

Background: Metabolic Syndrome (MetS) is a multifactorial condition characterized by insulin resistance, dyslipidemia, hypertension, and abdominal obesity, which collectively increase the risk of type 2 diabetes mellitus and cardiovascular diseases. Lifestyle modification represents the first-line strategy in its management, whereas pharmacological interventions are complex and typically require long-term polypharmacotherapy. In this context, natural bioactive compounds with pleiotropic effects are gaining increasing attention. Among these, S-allyl cysteine (SAC), the major sulfur-containing compound derived from black garlic, has been identified as a promising candidate due to its well-documented antioxidant and anti-inflammatory properties. Methods: This narrative review examines the pathophysiological mechanisms underlying MetS and summarizes current evidence on the protective role of SAC against key pathological features of this condition, including oxidative stress, inflammation, glucose and lipid dysmetabolism, endothelial dysfunction, and gut microbiota alterations. Results: Preclinical studies indicate that SAC counteracts lipid accumulation, insulin resistance, endothelial dysfunction, and gut dysbiosis through multiple mechanisms, including hydrogen sulfide release, reactive oxygen species scavenging, inhibition of advanced glycation end products, and modulation of metabolic pathways. Conclusions: SAC emerges as a promising nutraceutical for the prevention and management of MetS and its complications. This underscores the broader relevance of nutraceuticals as promising tools in mitigating metabolic dysfunctions and reducing the burden of cardiometabolic diseases. Full article

Anaerobic digestion is a well-known technology for renewable energy generation. Its efficiency depends on the substrate composition and its biodegradability. Microalgae are considered a promising feedstock due to their rapid growth, high protein and lipid content, and potential for wastewater treatment. However, the mono-digestion is often limited by a low carbon-to-nitrogen (C/N) ratio and a recalcitrant cell wall structure. This study evaluated the potential of co-digesting microalgal biomass with bakery waste under batch conditions. Two types of bakery residues (stale wheat bread and stale wheat rolls), were tested. Each was added to the microalgal biomass at proportions of 25%, 50%, and 75% based on volatile solids (VS). The experiment was carried out in a semi-technical anaerobic digester under mesophilic conditions. During the anaerobic digestion, the biogas volume, gas composition, and the energy potential of the substrates were analysed. The highest biogas yield (494.34 L·kg⁻¹ VS) was obtained from the mixture of microalgae and 75% bread. Although mono-digestion of microalgal biomass resulted in the highest methane concentration, the differences compared to co-digested samples were not significant. The lowest hydrogen sulphide concentration (234.20 ppm) was measured in the 25% rolls variant, while the control sample (100% microalgae) showed the highest H₂S levels. From an energy perspective, the most beneficial result was obtained with the addition of 75% bread. Full article

Plant growth-promoting rhizobacteria (PGPRs) colonise the rhizosphere and root surfaces, enhancing crop development through a variety of mechanisms. This study evaluated microbial strains isolated from Triticum aestivum L. for key plant growth-promoting traits, including indole-3-acetic acid (IAA) production, phosphate and zinc (Zn) solubilisation, nitrogen (N₂) fixation, and antifungal activity. Among 36 isolates, 3 (AS8, AS23, AS31) exhibited strong growth-promoting potential. IAA production, citrate assimilation, carbohydrate fermentation, and catalase activity were observed to a comparable extent among the selected strains. AS8 showed the highest protease, lipase, and amylolytic activity, while AS23 demonstrated superior phosphate and Zn solubilisation. Notably, AS31 emerged as the most promising multi-trait isolate, exhibiting the highest levels of IAA production, N₂ fixation, antifungal activity against five phytopathogens (Fusarium graminearum, F. solani, F. oxysporum, Pythium aphanidermatum, and Alternaria alternata), potentially linked to its hydrogen sulphide (H₂S) production, and cellulolytic activity. Molecular identification based on 16S rRNA gene sequencing revealed the isolates as Stenotrophomonas indicatrix AS8, Pantoea agglomerans AS23, and Bacillus thuringiensis AS31. Seed germination assays confirmed the plant growth-promoting efficacy of these PGPR strains, with vigour index increases of up to 43.4-fold. Given their positive impact on seed germination and significant Zn-solubilising abilities, the selected strains represent promising candidates for use as bio-inoculants, offering a sustainable and eco-friendly strategy to enhance agricultural productivity in nutrient-deficient soils. Future research should validate the efficacy of these PGPR strains under pot conditions to confirm their potential for practical agricultural applications. Full article

For a long time, D-amino acids remained unexplored in mammalian physiology. The technological advances in enantioseparation over the past 50 years have revealed that D-amino acids not only exist in human tissues and fluids but also play important roles in neurotransmission, immune regulation, and cellular proliferation. The present review provides a comprehensive assessment of the role of D-amino acids in cancer, including their endogenous and exogenous production pathways, along with the analytical methodologies used for detection and quantification, from liquid chromatography to biosensors. These methods have underlined how altered levels of D-amino acids can be helpful in early detection, progression, or response to treatment in several malignancies, including gastric, hepatic, colorectal, or breast cancer. The present review also explores how manipulation of D-amino acids can regulate cell proliferation, their mechanisms in cancer regulation, including the modulation of N-methyl-D-aspartate (NMDA) receptors and the production of hydrogen sulphide (H₂S), and the role of specific D-amino acids in cancer onset, immune defence, and protection against chemotherapy-induced toxicity. Finally, several underexplored research directions are outlined, such as potential correlations with gut microbiota composition, the impact of processed food consumption, and the integration of multiomics strategies. Full article

Biological reduction of sulphates has gradually replaced unit chemical processes for the treatment of acid mine drainage (AMD), which exerts a significant environmental impact due to its elevated acidity and high concentrations of heavy metals. Bioremediation is optimally suited for the treatment of AMD because it is cost-effective and efficient. Anaerobic bioremediation employing sulphate-reducing bacteria (SRB) presents a promising solution by facilitating the reduction of sulphate to sulphide. The formed can precipitate and immobilise heavy metals, assisting them in their removal from contaminated wastewater. This paper examines the current status of SRB-based bioremediation, with an emphasis on recent advances in microbial processes, reactor design, and AMD treatment efficiencies. Reviewed studies showed that SRB-based bioreactors can achieve up to 93.97% of sulphate reduction, with metal recovery rates of 95% for nickel, 98% for iron and copper, and 99% for zinc under optimised conditions. Furthermore, bioreactors that used glycerol and ethanol as a carbon source improved the efficiency of sulphate reduction, achieving a pH neutralisation from 2.8 to 7.5 within 14 days of hydraulic retention time. Despite the promising results achieved so far, several challenges remain. These include the need for optimal environmental conditions, the management of toxic hydrogen sulphide production, and the economic feasibility of large-scale applications. Future directions are proposed to address these challenges, focusing on the genetic engineering of SRB, integration with other treatment technologies, and the development of cost-effective and sustainable bioremediation strategies. Ultimately, this review provides valuable information to improve the efficiency and scalability of SRB-based remediation methods, contributing to more sustainable mining practices and environmental conservation. To ensure relevance and credibility, relevance and regency were used as criteria for the literature search. The literature sourced is directly related to the subject of the review, and the latest research, typically from the last 5 to 10 years, was prioritised. Full article