High Acid Research Articles

Identification and Functional Analysis of Key Genes Regulating Organic Acid Metabolism in Jujube Fruit

Organic acids are crucial indicators of fruit flavor quality, but the metabolic characteristics and regulatory genes of organic acids during jujube fruit development remain largely unexplored. In this study, the cultivar ‘Heigeda’ with a high organic acid content was used as the experimental material. The organic acid content was quantified, and key candidate genes were identified through transcriptome analysis. The results indicated that malic acid and citric acid were the main organic acid content in jujube fruit and increased gradually with fruit development. Transcriptome analysis identified nine genes associated with malic acid and seven with citric acid, with four genes co-regulating malic acid and citric acid. Functional assays by transient overexpression and silencing of these four genes in the jujube fruits revealed that overexpression significantly upregulated the malic and citric acid content. However, only the silencing of aconitase1 (ZjACO1) and aconitase3 (ZjACO3) significantly downregulated the content of malic and citric acids. Therefore, aconitase1 (ZjACO1) and aconitase3 (ZjACO3) are considered the key genes that regulate the metabolism of citric acid and malic acid in jujube fruits. Our study can enrich the regulation mechanism of the organic acid metabolism of jujube fruit and provide theoretical support for the efficient cultivation of jujube fruit.

Elucidating Bile Acid Tolerance in Saccharomyces cerevisiae: Effects on Sterol Biosynthesis and Transport Protein Expression.

The tolerance of Saccharomyces cerevisiae to high concentrations of bile acids is intricately linked to its potential as a probiotic. While the survival of yeast under high concentrations of bile acids has been demonstrated, the specific mechanisms of tolerance remain inadequately elucidated. This study aims to elucidate the tolerance mechanisms of S. cerevisiae CEN.PK2-1C under conditions of elevated bile acid concentrations. Through growth curve analyses and scanning electron microscopy (SEM), we examined the impact of high bile acid concentrations on yeast growth and cellular morphology. Additionally, transcriptomic sequencing and molecular docking analyses were employed to explore differentially expressed genes under high bile acid conditions, with particular emphasis on ATP-binding cassette (ABC) transporters and steroid hormone biosynthesis. Our findings indicate that high concentrations of bile acids induce significant alterations in the sterol synthesis pathway and transporter protein expression in S. cerevisiae. These alterations primarily function to regulate sterol synthesis pathways to maintain cellular structure and sustain growth, while enhanced expression of transport proteins improves tolerance to elevated bile acid levels. This study elucidates the tolerance mechanisms of S. cerevisiae under high bile acid conditions and provides a theoretical foundation for optimizing fermentation processes and process control.

Modified throughput ninhydrin method for the qualitative assessment of dietary protein absorption in pig plasma.

Protein maldigestion and malabsorption lead to malnutrition and are a feature of exocrine pancreatic insufficiency (EPI). Although it is the current standard, measurement of nitrogen in stool to assess protease activity is indirect. Up to 80% of hydrolysed proteins appear in blood in the form of peptides, so we developed a method to measure peptide-derived amino acids in plasma as a relevant measure of proteolysis, verified its accuracy, precision, and linearity, and validated it in a porcine model. We modified a ninhydrin method. Large proteins were eliminated from plasma with 10 kDa-cut-off centrifugal filters. Free and total amino acids were measured in permeate before and after its hydrolysis. Peptide-derived amino acids were quantified by subtracting free amino acids from total amino acids. We verified the method in vitro and by comparing results in healthy and EPI pigs. The accuracy of the analysis was close to 100%, with excellent precision (mean relative standard deviation for low, medium, and high amino acid levels = 0.88%) and with stringent linearity (r2 = 0.986, %RE = 5.23). The high-throughput ninhydrin method detected levels of peptide-derived amino acids in vivo with maximal changes seen approximately 2 hours postprandially in young pigs. The AUC and Cmax were significantly higher in healthy compared to EPI pigs (P = .0026 and P = .0037, respectively). The high-throughput ninhydrin method is a sensitive, reliable, and practical method for the estimation of dietary peptide-derived amino acids. This assay endpoint could serve as a direct biomarker of protein digestion and absorption.

An ultrastable luminescent covalent organic polymer for selective Pd2+ detection in strong acid

AbstractThe low natural abundance of palladium (10 ppb) in the Earth's crust highlights its considerable potential as a valuable resource, especially given that spent nuclear fuel contains approximately 1–2 kg of Pd per ton. However, the detection and separation of Pd2+ from high‐level liquid waste (HLLW) present significant challenges due to high acidity (2–5 M HNO3) and intense radiation conditions inherent in spent fuel reprocessing. We present a cyano‐olefin‐linked covalent organic polymer (COP‐TnPp) that exhibits remarkable stability in strong acidic environments and resilience to radiation. Thanks to its olefin linkage, which facilitates π‐electron conjugation, COP‐TnPp exhibits strong luminescence, whose intensity remains stable across a range of 1–5 M nitric acid solutions. Pd2+ ions can effectively quench the fluorescence of COP‐TnPp in 1 and 5 M HNO3 solutions with detection limits of 0.37 and 0.63 μM, respectively. Additionally, COP‐TnPp demonstrates exceptional selectivity for Pd2+ ions, even amidst 22 other interfering ions in a simulated HLLW solution (5 M HNO3), with the detection limit remaining at 0.697 μM. This work not only marks an advancement in the development of materials for detecting Pd2+ in extreme acidic conditions but also offers new insights into the detection of other radionuclides under similarly challenging environments.

Evaluation of the Physico-chemical and Biological Properties of Fermented Nipa (Nypa fruticans) Sap Under Closed and Open Vessel Fermentation System for Bioethanol Production

Background The potential of Nipa (Nypa fruticans) sap in the Cagayan Region, Philippines, for bioethanol production remains largely underexplored despite its vast expanse. Methods This study investigates the key physico-chemical properties of Nipa sap from Aparri, Cagayan, with a focus on fermentation dynamics and storage conditions to optimize ethanol production. Two fermentation treatments closed and open vessel conditions, were compared to determine the optimal conditions for maximum ethanol yield. Over a 7-day fermentation period, the acetic acid production, yeast activity, sugar content, and ethanol concentration of closed vessel fermented sap (CVFS) and open vessel fermented sap (OVFS) were monitored. Results CVFS demonstrated a higher ethanol yield (7.56%v/v at peak day), characterized by minimized acetic acid accumulation and stable yeast activity. In contrast, OVFS exhibited significant fluctuations in acetic acid and ethanol levels, indicating a lower fermentation efficiency. Conclusion The presence of methanol and high acetic acid content in open-vessel fermentation systems highlights the importance of fermentation conditions to prevent impurities. This study provides valuable insights into optimizing ethanol production from fermenting Nipa sap by employing closed vessel fermentation, which is crucial for sustainable bioethanol production in the Cagayan region.

Encapsulation of Lacticaseibacillus rhamnosus by Extrusion Method to Access the Viability in Saffron Milk Dessert and Under Simulated Gastrointestinal Conditions

ABSTRACTThe effectiveness of probiotics in delivering health benefits may be associated with their capacity to maintain a minimum concentration of 106 CFU/g during food storage and to successfully colonize the gastrointestinal tract (GI). Lacticaseibacillus rhamnosus (LR) is a probiotic that does not exhibit adequate stability under harsh conditions. To enhance the survival capacity of LR during gastrointestinal storage, alginate (ALG) was used as a primary encapsulating layer through extrusion microencapsulation. Subsequently, camelina seed mucilage (CSM) and camelina seed protein (CSP) were applied as secondary layers at varying concentrations (0%–4%). Among the tested formulations, ALG‐CSM‐CSP (1.5%, 4%, 4% w/w) exhibited significantly higher encapsulation efficiency (94.15%) and provided appropriate LR encapsulation in SEM image. Three saffron milk desserts (SMD) containing free LR (FLR), microencapsulated LR (MLR), and a control (C) were prepared, followed by physicochemical and microbiological assessments of the samples. The result showed that at the end of storage, SMD had the lowest pH (6.21), the highest acidity (30°D), and maintained the permissible limit of probiotic bacteria (6.7 log cfu/mL) among the samples. In GI, the MLR and FLR survival rates were 43% and 45.4%, respectively on the 14th day of storage, respectively. The MLR hardness (313.70 g), adhesiveness (2.01 mJ), chewiness (9.36) and gumminess (58.8) had the greatest values among the samples. Moreover, SEM images showed a relatively denser structure for MLR. In conclusion, this study highlights the potential of CSM and CSP to protect probiotics, offering valuable insights for developing new functional foods with improved survival during storage and GI.

Improved Antioxidant, Antihypertensive, and Antidiabetic Activities and Tailored Emulsion Stability and Foaming Properties of Mixture of Corn Gluten and Soy Protein Hydrolysates Via Enzymatic Processing and Fractionation

ABSTRACTBioactive peptides and protein hydrolysates have gained considerable attention in the food industry and functional food markets due to their diverse health effects, including antioxidant, antihypertensive, and antidiabetic properties. This study aimed to produce combined soy and corn protein hydrolysates using Alcalase (Al), modification of Al‐hydrolysates through sequential hydrolysis using Flavourzyme (Al‐FL), cross‐linking of Al‐hydrolysates using microbial transglutaminase (MTGase) (Al‐TG), and fractionation of Al‐hydrolysates by ultrafiltration (UF) with molecular weight (MW) cut‐off of 100 (Al‐F4), 30 (Al‐F3), 10 (Al‐F2), and 2 kDa (Al‐F1). Notably, the < 2 kDa fraction (Al‐F1) showcased exceptional biological activities, including antioxidant (81.54% DPPH, 98.02% ABTS), antihypertensive (95.45%), and antidiabetic effects (44.72% α‐glucosidase, 77.52% α‐amylase), linked to its high hydrophobic amino acid content and low molecular weights (111 and 263 Da). Conversely, the higher molecular weight fraction (Al‐TG) excelled in emulsion and foam stability, attributed to its balanced amino acid profile and larger peptides (1385–7057 Da). Our findings reveal that specific protein hydrolysate fractions, particularly Al‐F1 and Al‐TG, are promising for applications in food and pharmaceutical formulations due to their enhanced biological and functional properties.

Agribusiness Prospects of Kachai Lemon Produced in Ukhrul District of Manipur, India: Status, Issues and Way Forward

Kachai lemon (Citrus jambhiri Lush.) is a variety of citrus, known for its rich nutritional and medicinal benefits due to its high flavonoid content and ascorbic acid. It has played a significant role in enhancing the socio-economic development of the tribal communities by generating income and employment opportunities. The Geographical Indication (GI) tag awarded to Kachai lemon has increased its commercial cultivation and market value. This recognition and growing attention have led to the emergence of agripreneurs and farmer producer organizations (FPOs) for production, value addition and marketing of Kachai lemon in an organized manner. The present study is aimed to compile the success stories, challenges of farmers and explore various Kachai lemon brands available on online platforms. A SWOT (Strength, Weakness, Opportunities and Threats) analysis on production and marketing of kachai lemon was performed. For the study, descriptive analysis was carried out to assess its potential, current status and challenges. The study suggests that in order to compete globally, it is crucial to develop strong post-harvest processing and marketing systems with support from agencies and institutions to provide valuable resources and market linkages to enhance efficiency and gain economic benefits.

Volatilization and cleaning recovery of Pb, Se and Hg in acid sludge of copper smelting system during vacuum distillation

The high lead acid sludge, containing a small amount of selenium and mercury, is a hazardous waste product of the copper smelting system. Improper disposal of this waste can cause serious harm to the environment. In this study, the method of vacuum distillation was proposed for treating the high lead acid sludge. The study aimed to investigate the volatilization rule of selenium, mercury, and lead in the acid sludge during vacuum distillation, as well as to purify PbSe and metallic lead. The results indicated that under 5 Pa, Hg and Se commence volatilizing at 300 ℃, the content of Hg in volatile substances remains relatively constant after reaching 400 ℃, demonstrating nearly complete volatilization at this temperature with a ratio of 92.93 %. Similarly, selenium almost completely volatilizes at 800 ℃ with a ratio of 96.74 %, while lead does so at around 1000 ℃ with a ratio of approximately 99.27 %. Mercury at 400 ℃ can be recovered as mercury selenide. Lead selenide can be achieved at 800 ℃, while lead sulfate can be decomposed and purified at 1000 ℃ to obtain metallic lead with a purity higher than 99 %. The method can properly treat and recover mercury, selenium, lead and other elements in the acid sludge with short process and no pollution, which provides a new cleaning approach for high lead acid sludge.

Treatment of acidic crude palm oil using supported benzenesulfonic acid-based deep eutectic solvents in trickle bed reactor

In this study, a deep eutectic solvent (DES) from benzenesulfonic acid and choline chloride (BZSA-ChCl-DES) was prepared for the treatment of high free fatty acids (FFA) in acidic crude palm oil (ACPO). The DES was impregnated into activated carbon (AC-DES) to produce a supported catalyst used in a trickle bed reactor (TBR) for FFA esterification. Under optimal conditions, using 8 g of AC-DES at 60 °C, with ACPO and methanol flow rates of 1 mL/min and 4 mL/min, respectively, the TBR successfully treated 3.5 L of ACPO. A batch reactor, used for comparison, showed that the continuous TBR process required less catalyst per gram of treated oil (2.87 mg catalyst/g) which can enhance the recyclability. Moreover, the continuous process could sustain up to five recycle runs that can treat 1.5 L under optimal conditions (3.5 wt% catalyst dosage, 10:1 M ratio, 60 °C reaction temperature, and 30 min). This approach presents a promising continuous approach for converting high FFA to fatty acid methyl ester (FAME) for biodiesel production.

Lentil protein and trehalose conjugates: Structural interactions and mechanisms for improving multi-level structure and functional characteristics.

This study aimed to improve lentil proteins' (LPs) functionality and nutritional value, specifically addressing their lower water solubility and digestibility. A unique combination of LP-disaccharide interactions was employed. Spectroscopic technologies, which include fluorescence spectra, ultraviolet spectra, and Fourier-transform infrared, investigated the structure of LPs at various concentrations of trehalose. The results indicate that the LP structures and conformation were considerably modified (p<0.05) following trehalose conjugation. The surface charge and hydrophobicity of the trehalose-conjugated LPs (T-LPs) were significantly altered (p<0.05), from -22.7 to -31.4 and 753 and 543 a.u., respectively. Furthermore, the digestibility and solubility of T-LPs increased from 75% to 81.8% and 60% to 66%, respectively. In conclusion, this study showed that combining LPs and trehalose conjugation could improve the quality of conjugates LPs, which could expand their use in manufacturing as the acceptance of plant-based diets increases. PRACTICAL APPLICATION: Currently, lentil proteins (LPs) are used in plant-based protein powders and supplements. Though less popular than soy or pea proteins, LPs are valued for their high protein content and good amino acid profile. LPs are utilized in meat alternatives and high-protein snack products. The application of these products is mainly due to their nutritional benefits rather than functional properties due to their poor water solubility. Increasing the water solubility of LPs could significantly expand their application in various food industries, making LPs a more competitive and functional plant-based protein source. Trehalose-conjugated LPs with better water solubility allow LPs to be used in other food products, such as plant-based protein beverages. Better solubility would enhance the clarity and smoothness of these products, making them more appealing to consumers.

Influences of Lactiplantibacillus plantarum dy-1 Fermentation on the Bitterness of Bitter Melon Juice, the Composition of Saponin Compounds, and Their Bioactivities.

Lactic acid bacteria fermentation is a beneficial bioprocessing method that can improve the flavor, transform nutrients, and maintain the biological activity of foods. The aim of this study is to investigate the effects of Lactiplantibacillus plantarum dy-1 fermentation on the nutritional components, flavor and taste properties, and composition of saponin compounds and their hypolipidemic and antioxidant activities. The results suggested that the total polyphenol content increased, and the soluble polysaccharides and total saponin contents decreased in fermented bitter melon juice (FJ) compared with those in non-fermented bitter melon juice (NFJ). The determination of volatile flavor substances by GC-MS revealed that the response values of acetic acid, n-octanol, sedumol, etc., augmented significantly, and taste analysis with an electronic tongue demonstrated lower bitterness and higher acidity in FJ. Furthermore, UPLC-Q-TOF-MS/MS testing showed a significant decrease in bitter compounds, including momordicines I and II, and a significant increase in the active saponin momordicine U in the fermented bitter melon saponin group (FJBMS). The in vitro assays indicated that FJBMS exhibited similar antioxidant activities as the non-fermented bitter melon saponin group (NFBMS). The in vitro results show that both NFBMS and FJBMS, when used at 50 μg/mL, could significantly reduce fat accumulation and the malondialdehyde (MDA) content and increased the catalase (CAT) activity, while there was no significant difference in the bioactivities of NFBMS and FJBMS. In conclusion, Lactiplantibacillus plantarum dy-1 fermentation is an effective means to lower the bitterness value of bitter melon and preserve the well-known bioactivities of its raw materials, which can improve the edibility of bitter melon.

Folic acid supplementation during fattening period affects growth and nutritional metabolism in Japanese Black beef cattle

The folate requirements for beef cattle have not been established. Therefore, we investigated whether rumen-unprotected folic acid supplementation during the fattening period affects carcass traits and nutritional metabolism in Japanese Black beef cattle. Eighteen Beef cattle aged 16 months were divided into three groups: control, low folic acid supplementation (0.43 g DM/day), and high folic acid supplementation (0.86 g DM/day). Treatment was administered for 12 months. Folic acid supplementation dose-dependently increased serum folate levels, suggesting that supplemental folic acid can be absorbed into the body. Folic acid supplementation dose-dependently decreased serum vitamin B12 levels, while plasma total homocysteine and methylmalonic acid levels—markers for deficiency of folate and/or vitamin B12—were unaffected. Thus, the treatment did not clearly affect the nutritional status of these vitamins. Supplementation increased body weight, with no negative effects on other carcass traits. The levels of insulin-like growth factor 1, retinol, albumin, and some amino acids in serum or plasma were affected by supplementation. These results suggest that rumen-unprotected folic acid supplementation during the fattening period could increase the body weight of Japanese Black beef cattle and the mechanism of action may be related to growth-related hormones and/or the metabolism of some nutrients, including folate.

Febuxostat in patients with hyperuricemia and gout: is the nephroprotective effect real?

Hyperuricemia (HU) and gout are independent risk factors for chronic kidney disease (CKD). Worldwide, the increasing prevalence of CKD leads to a deterioration in the quality and duration of life of patients and an increase in mortality. If HU plays a significant role in the development of renal failure, then lowering high uric acid (UA) levels should theoretically contribute to the improvement of kidney function. The main method of lowering UA levels is administration of a urate-lowering therapy – xanthine oxidase (XO) inhibitors. The nephroprotective effect of one of the XO inhibitors, febuxostat has been demonstrated in animal models.The article analyzes the currently available data on the use of febuxostat in patients with HU and gout and different levels of renal function impairment and discusses the possible mechanisms of the drug's nephroprotective effect.

Sirt1-mediated deacetylation of PGC-1α alleviated hepatic steatosis in type 2 diabetes mellitus via improving mitochondrial fatty acid oxidation

Being activated by deacetylation, peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) has become an important regulator of metabolic-related diseases. The activation of Sirtuin 1 (Sirt1) by resveratrol was likely to deacetylate PGC-1α. However, the role of deacetylated PGC-1α in the alleviation of activated Sirt1 on type 2 diabetes mellitus (T2DM)-related fatty liver disease (FLD) remained unexplored. The aim of this study was to investigate the potential impact of Sirt1-mediated deacetylation of PGC-1α on T2DM-associated FLD and its underlying mechanisms. Our findings revealed that, along with the decreased Sirt1, the levels of acetylated PGC-1α were up-regulated in hepatocytes co-stimulated with high glucose (HG) and free fatty acids (FFA). Down-regulated Sirt1 inactivated PGC-1α by inhibiting its deacetylation, while activating Sirt1 improved hepatic injury by reducing lipid droplet accumulation through the deacetylation of PGC-1α. However, the beneficial effects of Sirt1 activation on hepatic steatosis were inhibited by PGC-1α antagonist in vitro. Mechanistically, activating Sirt1 enhanced mitochondrial function by promoting PGC-1α activity, thereby facilitating hepatic fatty acid oxidation (FAO). In conclusion, Sirt1-mediated deacetylation of PGC-1α mitigated hepatic lipotoxicity by enhancing mitochondrial FAO, which contributed to the restoration of mitochondrial function in T2DM. The activation of Sirt1-mediated PGC-1α deacetylation might represent a promising therapeutic approach for T2DM-associated FLD.

Clinical rationale for dietary lutein supplementation in long COVID and mRNA vaccine injury syndromes.

Lutein, a plant-derived xanthophyl-carotenoid, is an exceptional antioxidant and anti-inflammatory constituent found in food. High dietary intake of lutein is beneficial against eye disease, improves cardiometabolic health, protects from neurodegenerative diseases, and is beneficial for liver, kidney, and respiratory health. Lutein protects against oxidative and nitrosative stress, both of which play a major role in long COVID and mRNA vaccination injury syndromes. Lutein is an important natural agent for therapeutic use against oxidative and nitrosative stress in chronic illnesses such as cardiovascular and neurodegenerative diseases and cancer. It can also potentially inhibit spike protein-induced inflammation. Rich dietary supplementation of lutein, naturally derived in non-biodegradable Extra Virgin Olive Oil (EVOO), can most optimally be used against oxidative and nitrosative stress during post-COVID and mRNA vaccination injury syndromes. Due to its high oleic acid (OA) content, EVOO supports optimal absorption of dietary lutein. The main molecular pathways by which the SARS-CoV-2 spike protein induces pathology, nuclear factor kappa-light-chain-enhancer activated B cells (NF-κB) and activated protein (AP)-1, can be suppressed by lutein. Synergy with other natural compounds for spike protein detoxification is likely.

Reconfiguring the Escherichia coli Electron Transport Chain to Enhance trans-2-Decenoic Acid Production.

trans-2-Decenoic acid is a pivotal α,β-medium-chain unsaturated fatty acid that serves as an essential intermediary in the synthesis of 10-hydroxy-2-decenoic acid and various pharmaceutical compounds. Biosynthesis yield of trans-2-decenoic acid by decanoic acid has significantly improved in recent years; however, the oxidative stress of Escherichia coli at high fatty acid concentrations restricts the conversion rate. Here, we introduced a combination of rational design and metabolic rewiring of the E. coli electron transport chain (ETC) to improve trans-2-decenoic acid production. Overexpressing ubiquinone (UbQ) biosynthesis genes enhanced the expression of ETC complex III: UbQ to reduce reactive oxygen species (ROS) accumulation. Furthermore, applying rotenone to inhibit ETC complex I improved the electron transfer efficiency of complex II. The integration of Vitamin B5 and B2 into the fermentation process increased the activities of fatty acyl-CoA synthetase (MaMACS) and fatty acyl-CoA dehydrogenase (PpfadE). Finally, the constructed E. coli BL21(DE3)(ΔfadBJR/pCDFDuet-1-PpfadE-MaMACS/pRSFDuet-1-sumo-CtydiI-ubiI) strain exhibited a 51.50% decrease in ROS and a 93.33% enhancement in trans-2-decenoic acid yield, reaching 1.45 g/L after 66 h, which is the highest yield reported for flask fermentation. This study reports the feasibility of rewiring the ETC regulation and energy metabolism to improve α,β-UCA biosynthesis efficiency.

Clavulanic Acid Overproduction: A Review of Environmental Conditions, Metabolic Fluxes, and Strain Engineering in Streptomyces clavuligerus

Clavulanic acid is a potent β-lactamase inhibitor produced by Streptomyces clavuligerus, widely used in combination with β-lactam antibiotics to combat antimicrobial resistance. This systematic review analyzes the most successful methodologies for clavulanic acid overproduction, focusing on the highest yields reported in bench-scale and bioreactor-scale fermentations. Studies have demonstrated that glycerol is the preferred carbon source for clavulanic acid production over other sources like starch and dextrins. The optimization of feeding strategies, especially in fed-batch operations, has improved glycerol utilization and extended the clavulanic acid production phase. Organic nitrogen sources, particularly soybean protein isolates and amino acid supplements such as L-arginine, L-threonine, and L-glutamate, have been proven effective at increasing CA yields both in batch and fed-batch cultures, especially when balanced with appropriate carbon sources. Strain engineering approaches, including mutagenesis and targeted genetic modifications, have allowed for the obtainment of overproducer S. clavuligerus strains. Specifically, engineering efforts that overexpress key regulatory genes such as ccaR and claR, or that disrupt competing pathways, redirect the metabolic flux towards CA biosynthesis, leading to high clavulanic acid titers. The fed-batch operation at the bioreactor scale emerges as the most feasible alternative for prolonged clavulanic acid production with both wild-type and mutant strains, allowing for the attainment of high titers during cultivations.

Property-Wound Healing Relationship of Manuka-, Anzer- and Chestnut-Honey: Characterization, Antibacterial Properties and Cell Culture Applications

Honey is known to be a natural food product with antibacterial and wound-healing properties. Among its different types, some attributed more with medical applications including Manuka honey. In this study, some wound healing-related parameters were systematically investigated on two different types of Turkish honey (Chestnut and Anzer), in comparison with Manuka honey. Chestnut honey had considerable amount of hydrogen peroxide (5 μg/mL) whereas Manuka and Anzer honey did not contain any. Additionally, Chestnut honey had the highest acidity among all tested samples (24.50 meq/kg), as well as higher antioxidant activity (IC50 ; 2.45 mg/ml) than those of Anzer (13.02 mg/ml) and Manuka honey (6.27 mg/ml). It was also demonstrated that Chestnut honey displayed a considerable antimicrobial activity against selected pathogens. On the other hand, in the scratch assay performed as a model for the wound healing process, Anzer honey induced the highest cell proliferation corresponding to almost total wound closure for all concentrations tested. Overall, the results showed that the Turkish Chestnut and Anzer honey samples had distinguished characteristics for wound healing that is comparable to Manuka honey, and therefore are both promising candidates for use in clinical applications.

Impact of Top-Down Regulation on the Growth Efficiency of Freshwater Bacterioplankton

To investigate the hypothesis of top-down control by viruses and heterotrophic nanoflagellates on bacterial-mediated carbon fluxes in freshwater systems, a year-long study (2023–2024) was conducted in the pelagic zone of Lake Saint-Gervais (France). The variability in BGE (9.9% to 45.5%) was attributed to the decoupling of production and respiration, providing bacterioplankton communities with a competitive advantage in adapting to fluctuating environmental disturbances in freshwater systems. The high nucleic acid (HNA) bacterial community, the active fraction, contributed the most to bacterial production and was linked to BGE estimates. Weak bottom-up controls (nutrient concentrations and stoichiometry) on BGE suggested a stronger role for mortality forces. Among viral subgroups (VLP1–VLP4) identified via flow cytometry, the dominant low-fluorescence DNA VLP1 subgroup (range = 0.7 to 3.1 × 108 VLP mL−1) accounting for the majority of viral production was closely linked to the HNA population. Both top-down forces exerted antagonistic effects on BGE at the community level. The preferential lysis and grazing of the susceptible HNA population, which stimulated bacterial community respiration more than production in the non-target population, resulted in reduced BGE. These results underscore the key role of top-down processes in shaping carbon flux through bacterioplankton in this freshwater system.