Investigation of antifungal and antibacterial potential of green extracts of propolis.

Propolis extracts have been used in traditional medicines since ages due to its advantageous complex chemical composition. However, the antibacterial and antifungal activity of poplar propolis extracts prepared in Natural Deep Eutectic Solvent (NADES) are seldom studied. This study investigates suitable alternate for ethanol as a solvent for extraction for Polish poplar propolis. It also attempts to identify suitable extraction condition for the efficient transfer of compounds from propolis to the solvents. The extraction efficiency of NADES extracts was assessed in terms of total phenolic content, antioxidant activity and antimicrobial activity. The chemical composition of the extracts was analysed using UHPLC-DAD-QqTOF-MS. Four extracts, prepared in Propylene Glycol, Choline Chloride:Propylene Glycol (1:3), Choline Chloride:Propylene Glycol (1:4) and Choline Chloride:Glycerol (1:2), demonstrated activity and properties similar to ethanolic extract and extraction at 50 °C was found the most suitable for propolis. HPLC analysis confirmed that the chemical cocktail extracted by these solvents from propolis were identical with minor variations in their concentration as compared to its ethanolic extract. Thus, extracts of propolis at 50 °C in Propylene Glycol, Choline Chloride:Propylene Glycol (1:3) and Choline Chloride:Propylene Glycol (1:4) can be alternates for ethanolic extracts.

Digital Photocolorimetric Analysis of In Vitro Tooth Color Changes.

OBJECTIVE: Tooth color matching is challenging, and digital photocolorimetry using eLABor_aid (eLAB) provides objective evaluation through polarized photographs. However, its comparability with spectrophotometry remains unclear. METHODS AND MATERIALS: Bovine incisor root canals (n=30) were prepared to simulate an incomplete root apex. The teeth were randomly assigned to three groups based on intracanal medication: control (without medication); calcium hydroxide/propylene glycol; and triple-antibiotic paste (n=10 each). Tooth color was assessed using both eLAB and spectrophotometry. Measurements were taken at the crown medio-cervical region on five-time intervals (baseline, 1, 3, 7, and 14 days). Statistical analysis included two-way repeated-measures ANOVA, Sidak post hoc and Pearson's correlation test (α=0.05). RESULTS: No significant differences were observed between the two methods for either medication or follow-ups (p>0.05). Triple-antibiotic paste exhibited higher color variation (p<0.05). After 7 days, all groups presented significant color changes (p<0.05). Moderate to high correlations (R2 from 0.51 to 0.84, p<0.0001) were found between both methods for all groups at all intervals. CONCLUSION: The eLAB is a reliable method for detecting tooth color changes, and its results are comparable to spectrophotometry analysis.

Pitfalls in the Detection of Volatiles Associated with Heated Tobacco and e-Vapor Products When Using PTR-TOF-MS.

We investigated the applicability of proton transfer reaction-time-of-flight mass spectrometry (PTR-TOF-MS) for quantitative analysis of mixtures comprising glycerin, acetol, glycidol, acetaldehyde, acetone, and propylene glycol. While PTR-TOF-MS offers real-time simultaneous determination, the method selectivity is limited when analyzing compounds with identical elemental compositions or when labile compounds present in the mixture produce fragments that generate overlapping ions with other matrix components. In this study, we observed significant fragmentation of glycerin, acetol, glycidol, and propylene glycol during protonation via hydronium ions (H3O+). Nevertheless, specific ions generated by glycerin (m/z 93.055) and propylene glycol (m/z 77.060) enabled their selective detection. To thoroughly investigate the selectivity of the method, various mixtures containing both isotope-labeled and unlabeled compounds were utilized. The experimental findings demonstrated that when samples contained high levels of glycerin, it was not feasible to perform time-resolved analysis in H3O+ mode for acetaldehyde, acetol, and glycidol. To overcome the observed selectivity limitations associated with the H3O+ reagent ions, alternative ionization modes were investigated. The ammonium ion mode proved appropriate for analyzing propylene glycol (m/z 94.086) and acetone (m/z 76.076) mixtures. Concerning the nitric oxide mode, specific m/z were identified for acetaldehyde (m/z 43.018), acetone (m/z 88.039), glycidol (m/z 73.028), and propylene glycol (m/z 75.044). It was concluded that considering the presence of multiple product ions and the potential influence of other compounds, it is crucial to conduct a thorough selectivity assessment when employing PTR-TOF-MS as the sole method for analyzing compounds in complex matrices of unknown composition.

Structural and aggregation changes of silver carp myosin induced with alcohols: Effects of ethanol, 1,2-propanediol, and glycerol.

This study investigated the effects of ethanol, 1,2-propanediol, and glycerol on the structure and aggregation behavior of silver carp (Hypophthalmichthys molitrix) myosin. All alcohols induced extensive alteration in the tertiary structure of myosin. Both ethanol and 1,2-propanediol further promoted an increase in the content of ß-sheets in myosin and induced myosin aggregation. While glycerol had almost no impact on the secondary structure of myosin. Molecular dynamics simulations revealed that increasing the concentration of ethanol and 1,2-propanediol affected the overall structural changes in the myosin heavy chain (MHC), while glycerol exerted a more pronounced effect on the MHC tail when compared to the MHC head. Disruption of the hydration layers induced by ethanol and 1,2-propanediol contributed to local structural changes in myosin. Glycerol at a concentration of 20% induced the formation of a larger hydration layer around the MHC tail, which facilitated the stabilization of the protein structure.

Mechanisms of the Drug Penetration Enhancer Propylene Glycol Interacting with Skin Lipid Membranes.

Very few drugs have the necessary physicochemical properties to cross the skin's main permeability barrier, the stratum corneum (SC), in sufficient amounts. Propylene glycol (PG) is a chemical penetration enhancer that could be included in topical formulations in order to overcome the barrier properties of the skin and facilitate the transport of drugs across it. Experiments have demonstrated that PG increases the mobility and disorder of SC lipids and may extract cholesterol from the SC, but little is known about the molecular mechanisms of drug permeation enhancement by PG. In this work, we have performed molecular dynamics (MD) simulations to investigate the molecular-level effects of PG on the structure and properties of model SC lipid bilayers. The model bilayers were simulated in the presence of PG concentrations over the range of 0-100% w/w PG, using both an all-atom and a united atom force field. PG was found to localize in the hydrophilic headgroup regions at the bilayer interface, to occupy the lipid-water hydrogen-bonding sites, and to slightly increase lipid tail disorder in a concentration-dependent manner. We showed with MD simulation that PG enhances the permeation of small molecules such as water by interacting with the bilayer interface; the results of our study may be used to guide the design of formulations for transdermal drug delivery with enhanced skin permeation, as well as topical formulations and cosmetic products.

Investigation of the in vitro toxic effects induced by real-time aerosol of electronic cigarette solvents using microfluidic chips.

The safety of propylene glycol (PG) and vegetable glycerin (VG) as solvents in electronic cigarette liquid has received increasing attention and discussion. However, the conclusions derived from toxicity assessments conducted through animal experiments and traditional in vitro methodologies have consistently been contentious. This study constructed an original real-time aerosol exposure system, centered around a self-designed microfluidic bionic-lung chip, to assess the biological effects following exposure to aerosols from different solvents (PG, PG/VG mixture alone and PG/VG mixture in combination with nicotine) on BEAS-2B cells. The study aimed to investigate the impact of aerosols from different solvents on gene expression profiles, intracellular biomarkers (i.e., reactive oxygen species content, nitric oxide content, and caspase-3/7 activity), and extracellular biomarkers (i.e., IL-6, IL-8, TNF-α, and malondialdehyde) of BEAS-2B cells on-chip. Transcriptome analyses suggest that ribosomal function could serve as a potential target for the impact of aerosols derived from various solvents on the biological responses of BEAS-2B cells on-chip. And the results showed that aerosols of PG/VG mixtures had significantly less effect on intracellular and extracellular biomarkers in BEAS-2B cells than aerosols of PG, whereas increasing nicotine levels might elevate these effects of aerosol from PG/VG mixture.

Reviewing the evidence of antimicrobial activity of glycols.

In the 1940s and 1950s, researchers seeking safe and novel ways to eliminate airborne pathogens from enclosed spaces, investigated glycol vapours as a method of disinfection. More recently, the COVID-19 pandemic highlighted the need for a non-toxic aerial disinfectant that can be used in the presence of people. This scoping review is intended to analyse the early and more recent literature on glycol disinfection, scrutinizing the methodologies used, and to determine if the use of glycols as modern-day disinfectants is justified PRISMA-ScR guidelines were used to assess the 749 articles retrieved from the Web of Science platform, with 46 articles retained after the search strategy was applied. Early studies generally demonstrated good disinfection capabilities against airborne bacteria and viruses, particularly with propylene glycol (PG) vapour. Vapour pressure, relative humidity, and glycol concentration were found to be important factors affecting the efficacy of glycol vapours. Contact times depended mainly on the glycol application method (i.e. aerosolization or liquid formulation), although information on how glycol efficacy is impacted by contact time is limited. Triethylene glycol (TEG) is deemed to have low toxicity, carcinogenicity, and mutagenicity and is registered for use in air sanitization and deodorization by the US Environmental Protection Agency. Glycols are also used in liquid formulations for their antimicrobial activity against a wide range of microorganisms, although when used as a non-active excipient in products, their contribution to antimicrobial efficacy is rarely assessed. The appropriate use of liquid glycol-containing formulations was found to positively impact the antimicrobial capabilities of disinfectants when used at temperatures <0, food preservatives, and dental medicaments. Providing modern delivery technology can accurately control environmental conditions, the use of aerosolized glycol formulations should lead to successful disinfection, aiding infection prevention, and control regimens.

The effect of three additives on properties of mineral trioxide aggregate cements: a systematic review and meta-analysis of in vitro studies.

BACKGROUND: Several efforts have been made to improve mechanical and biological properties of calcium silicate-based cements through changes in chemical composition of the materials. This study aimed to investigate the physical (including setting time and compressive strength) and chemical (including calcium ion release, pH level) properties as well as changes in cytotoxicity of mineral trioxide aggregate (MTA) after the addition of 3 substances including CaCl2, Na2HPO4, and propylene glycol (PG). METHODS: The systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Electronic searches were performed on PubMed, Embase, and Scopus databases, spanning from 1993 to October 2023 in addition to manual searches. Relevant laboratory studies were included. The quality of the included studies was assessed using modified ARRIVE criteria. Meta-analyses were performed by RevMan statistical software. RESULTS: From the total of 267 studies, 24 articles were included in this review. The results of the meta-analysis indicated that addition of PG increased final setting time and Ca2+ ion release. Addition of Na2HPO4 did not change pH and cytotoxicity but reduced the final setting time. Incorporation of 5% CaCl2 reduced the setting time but did not alter the cytotoxicity of the cement. However, addition of 10% CaCl2 reduced cell viability, setting time, and compressive strength. CONCLUSION: Inclusion of 2.5% wt. Na2HPO4 and 5% CaCl2 in MTA can be advisable for enhancing the physical, chemical, and cytotoxic characteristics of the admixture. Conversely, caution is advised against incorporating elevated concentrations of PG due to its retarding effect. TRIAL REGISTRATION: PROSPERO registration number: CRD42021253707.

A genome-reduced Corynebacterium glutamicum derivative discloses a hidden pathway relevant for 1,2-propanediol production.

BACKGROUND: 1,2-propanediol (1,2-PDO) is widely used in the cosmetic, food, and drug industries with a worldwide consumption of over 1.5 million metric tons per year. Although efforts have been made to engineer microbial hosts such as Corynebacterium glutamicum to produce 1,2-PDO from renewable resources, the performance of such strains is still improvable to be competitive with existing petrochemical production routes. RESULTS: In this study, we enabled 1,2-PDO production in the genome-reduced strain C. glutamicum PC2 by introducing previously described modifications. The resulting strain showed reduced product formation but secreted 50 ± 1 mM D-lactate as byproduct. C. glutamicum PC2 lacks the D-lactate dehydrogenase which pointed to a yet unknown pathway relevant for 1,2-PDO production. Further analysis indicated that in C. glutamicum methylglyoxal, the precursor for 1,2-PDO synthesis, is detoxified with the antioxidant native mycothiol (MSH) by a glyoxalase-like system to lactoylmycothiol and converted to D-lactate which is rerouted into the central carbon metabolism at the level of pyruvate. Metabolomics of cell extracts of the empty vector-carrying wildtype, a 1,2-PDO producer and its derivative with inactive D-lactate dehydrogenase identified major mass peaks characteristic for lactoylmycothiol and its precursors MSH and glucosaminyl-myo-inositol, whereas the respective mass peaks were absent in a production strain with inactivated MSH synthesis. Deletion of mshA, encoding MSH synthase, in the 1,2-PDO producing strain C. glutamicum ΔhdpAΔldh(pEKEx3-mgsA-yqhD-gldA) improved the product yield by 56% to 0.53 ± 0.01 mM1,2-PDO mMglucose-1 which is the highest value for C. glutamicum reported so far. CONCLUSIONS: Genome reduced-strains are a useful basis to unravel metabolic constraints for strain engineering and disclosed in this study the pathway to detoxify methylglyoxal which represents a precursor for 1,2-PDO production. Subsequent inactivation of the competing pathway significantly improved the 1,2-PDO yield.

In vitro toxicological evaluation of aerosols generated by a 4th generation vaping device using nicotine salts in an air-liquid interface system.

BACKGROUND: Electronic cigarettes (EC) have gained popularity, especially among young people, with the introduction of fourth-generation devices based on e-liquids containing nicotine salts that promise a smoother vaping experience than freebase nicotine. However, the toxicological effects of nicotine salts are still largely unknown, and the chemical diversity of e-liquids limits the comparison between different studies to determine the contribution of each compound to the cytotoxicity of EC aerosols. Therefore, the aim of this study was to evaluate the toxicological profile of controlled composition e-liquid aerosols to accurately determine the effects of each ingredient based on exposure at the air-liquid interface. METHODS: Human lung epithelial cells (A549) were exposed to undiluted aerosols of controlled composition e-liquids containing various ratios of propylene glycol (PG)/vegetable glycerin (VG) solvents, freebase nicotine, organic acids, nicotine salts, and flavoured commercial e-liquids. Exposure of 20 puffs was performed at the air-liquid interface following a standard vaping regimen. Toxicological outcomes, including cytotoxicity, inflammation, and oxidative stress, were assessed 24 h after exposure. RESULTS: PG/VG aerosols elicited a strong cytotoxic response characterised by a 50% decrease in cell viability and a 200% increase in lactate dehydrogenase (LDH) production, but had no effects on inflammation and oxidative stress. These effects occurred only at a ratio of 70/30 PG/VG, suggesting that PG is the major contributor to aerosol cytotoxicity. Both freebase nicotine and organic acids had no greater effect on cell viability and LDH release than at a 70/30 PG/VG ratio, but significantly increased inflammation and oxidative stress. Interestingly, the protonated form of nicotine in salt showed a stronger proinflammatory effect than the freebase nicotine form, while benzoic acid-based nicotine salts also induced significant oxidative stress. Flavoured commercial e-liquids was found to be cytotoxic at a threshold dose of ≈ 330 µg/cm². CONCLUSION: Our results showed that aerosols of e-liquids consisting only of PG/VG solvents can cause severe cytotoxicity depending on the concentration of PG, while nicotine salts elicit a stronger pro-inflammatory response than freebase nicotine. Overall, aerosols from fourth-generation devices can cause different toxicological effects, the nature of which depends on the chemical composition of the e-liquid.

Considerations for deriving a safe intake of propylene glycol.

The use of propylene glycol (PG) in food and other applications is widespread, and some estimates of dietary exposure to PG approach or exceed the Acceptable Daily Intake (ADI) of 25 mg/kg bw-day. The current ADI for PG applies a cumulative uncertainty factor of 100, which includes factors of 10 for both interspecies and intraspecies differences. Available toxicology studies and human data, however, indicate a plausible mode of action (MoA) that would support a chemical-specific adjustment factor (CSAF) of 1 for interspecies toxicodynamic differences, reducing the total uncertainty factor from 100 to 40. The MoA involves an increase in serum PG concentrations after metabolic saturation, leading to serum hyperosmolarity, which can ultimately cause hemolytic changes and red blood cell damage. Therefore, the species similarities in toxicodynamic response for this critical effect could support increasing the ADI from 25 to 62.5 mg/kg bw-day, applicable to both children and adults.

Rational development of topical climbazole formulations.

Dandruff, or pityriasis capitis simplex, is a common scalp condition associated with excessive flaking and scaling of the epidermal tissue. Other features include irregular corneocyte turnover, irritation, itching and an impaired skin barrier function. Previously we reported the characterization of climbazole (CBZ), an antifungal agent used in the management of dandruff. Skin permeation of CBZ from neat solvents was also investigated. In the present work we evaluated CBZ permeation in human skin in vitro from more complex formulations that better represent products used by consumers. The various systems studied were composed of propylene glycol (PG), Transcutol®P (TC), octyl salicylate (OSal) and isopropyl alcohol (IPA). As well as measurement of skin uptake and penetration of CBZ, where possible, the skin retention and permeation of the various solvents was also determined. All vehicles promoted skin permeation of CBZ but no significant differences in amount permeated were evident between the binary vehicles (PG:TC, TC:OSal) and the ternary vehicle studied (PG:IPA:OSal). The binary vehicles generally promoted more skin uptake of CBZ compared with the neat solvents (PG, TC, OSal) studied previously. Permeation and skin extraction of CBZ from the PG:TC vehicles increased with increasing PG content; a similar trend was evident for the PG:IPA:OSal systems. New methods were developed and validated for measurement of PG, TC and OSal. Analysis of the individual solvents indicated that PG permeation was also independent of the amounts of other solvents in the binary or ternary systems. Consistent with previous findings higher proportions of TC permeated compared with PG for the PG:TC binary systems; TC also permeated the skin more rapidly than PG from these vehicles. For OSal, skin extraction was generally higher for TC:OSal compared with the PG:IPA:OSal vehicle. However, increasing the content of OSal did not appear to influence CBZ skin uptake nor permeation. Interestingly, the effects of the various PG:TC vehicles on CBZ skin delivery contrast with results we previous reported for the same systems for a different active. This confirms that with reference to skin permeation, formulation effects and/or skin penetration enhancement should be expected to vary and may not be predicted for specific vehicles.

Enhancement of Benzene Emissions in Special Combinations of Electronic Nicotine Delivery System Liquid Mixtures.

Electronic nicotine delivery systems (ENDS) are battery-powered devices introduced to the market as safer alternatives to combustible cigarettes. Upon heating the electronic liquid (e-liquid), aerosols are released, including several toxicants, such as volatile organic compounds (VOCs). Benzene has been given great attention as a major component of the VOCs group as it increases cancer risk upon inhalation. In this study, several basic e-liquids were tested for benzene emissions. The Aerosol Lab Vaping Instrument was used to generate aerosols from ENDS composed of different e-liquid combinations: vegetable glycerin (VG), propylene glycol (PG), nicotine (nic), and benzoic acid (BA). The tested mixtures included PG, PG + nic + BA, VG, VG + nic + BA, 30/70 PG/VG, and 30/70 PG/VG + nic + BA. A carboxen polydimethylsiloxane fiber for a solid-phase microextraction was placed in a gas cell to trap benzene emitted from a Sub-Ohm Minibox C device. Benzene was adsorbed on the fiber during the puffing process and for an extra 15 min until it reached equilibrium, and then it was determined using gas chromatography-mass spectrometry. Benzene was quantified in VG but not in PG or the 30/70 PG/VG mixtures. However, benzene concentration increased in all tested mixtures upon the addition of nicotine benzoate salt. Interestingly, benzene was emitted at the highest concentration when BA was added to PG. However, lower concentrations were found in the 30/70 PG/VG and VG mixtures with BA. Both VG and BA are sources of benzene. Enhanced emissions, however, are mostly noticeable when BA is mixed with PG and not VG.

Glycols: The ubiquitous solvent for dermal formulations.

Glycols stand out as one of the most commonly employed safe and effective excipients for pharmaceutical and cosmeceutical products. Their widespread adoption can be attributed to their exceptional solvency characteristics and their ability to interact effectively with skin lipids and keratin for permeation enhancement. Notably, propylene glycol enjoys significant popularity in this regard. Ongoing research endeavours have been dedicated to scrutinising the impact of glycols on dermal drug delivery and shedding light on the intricate mechanisms by which glycols enhance skin permeation. This review aims to mitigate the discordance within the existing literature, assemble a holistic understanding of the impact of glycols on the percutaneous absorption of active compounds and furnish the reader with a profound comprehension of the foundational facets pertaining to their skin permeation enhancement mechanisms, while simultaneously delving deeper into the intricacies of these processes.

Conventional and multi-omics assessments of subacute inhalation toxicity due to propylene glycol and vegetable glycerin aerosol produced by electronic cigarettes.

Propylene glycol (PG) and vegetable glycerin (VG) are the most common solvents used in electronic cigarette liquids. No long-term inhalation toxicity assessments have been performed combining conventional and multi-omics approaches on the potential respiratory effects of the solvents in vivo. In this study, the systemic toxicity of aerosol generated from a ceramic heating coil-based e-cigarette was evaluated. First, the aerosol properties were characterized, including carbonyl emissions, the particle size distribution, and aerosol temperatures. To determine toxicological effects, rats were exposed, through their nose only, to filtered air or a propylene glycol (PG)/ glycerin (VG) (50:50, %W/W) aerosol mixture at the target concentration of 3 mg/L for six hours daily over a continuous 28-day period. Compared with the air group, female rats in the PG/VG group exhibited significantly lower body weights during both the exposure period and recovery period, and this was linked to a reduced food intake. Male rats in the PG/VG group also experienced a significant decline in body weight during the exposure period. Importantly, rats exposed to the PG/VG aerosol showed only minimal biological effects compared to those with only air exposure, with no signs of toxicity. Moreover, the transcriptomic, proteomic, and metabolomic analyses of the rat lung tissues following aerosol exposure revealed a series of candidate pathways linking aerosol inhalation to altered lung functions, especially the inflammatory response and disease. Dysregulated pathways of arachidonic acids, the neuroactive ligand-receptor interaction, and the hematopoietic cell lineage were revealed through integrated multi-omics analysis. Therefore, our integrated multi-omics approach offers novel systemic insights and early evidence of environmental-related health hazards associated with an e-cigarette aerosol using two carrier solvents in a rat model.

Cross-Reactivity Between Propylene Glycol and Butylene Glycol.

Background: Propylene glycol (PG) and butylene glycol (BG) are not known to be cross-reactors. However, no large-scale studies have assessed the cross-reactivity rate (CRR) between these 2 structurally and functionally similar compounds. Objectives: The aim of this study was to determine whether PG and BG demonstrate cross-reactivity. Methods: This is a retrospective chart review of 893 patients who underwent patch testing for both PG and BG from 2020 to 2022. The frequencies of positive reactions and concomitant reaction rates were calculated. Results: In our cohort, 53 (5.94%) patients reacted to PG and 13 patients (1.46%) reacted to BG. Of the patients who reacted to PG, 6 reacted to BG representing a CRR of 11.3%, whereas the CRR to PG in BG-allergic patients was 46.2%. Conclusions: For those allergic to BG, PG should be considered a cross-reactor. This relationship is somewhat unidirectional, as patients allergic to PG demonstrated a CRR to BG of only 11.3%, significantly lower than the 46.2% CRR to PG among BG-allergic patients.

Effects of 1,3-propanediol associated, or not, with butylene glycol and/or glycerol on skin hydration and skin barrier function.

OBJECTIVE: This study aimed to assess the effect of 1,3-propanediol at different concentrations (5%, 10%, or 15%), either applied alone or in combination with butylene glycol (BG) (5%) and/or glycerol (5%), on skin hydration and skin barrier function. The measurements were conducted using capacitance to determine skin hydration and trans epidermal water loss (TEWL) rates to evaluate skin barrier function. METHODS: A total of 30 healthy female subjects participated in the study. Capacitance and TEWL measurements were conducted at multiple time points, including before application and at 15 min, 2 and 8 h after the humectants were applied to the forearms of the subjects. All the subjects provided written informed consent. RESULTS: The 1,3-propanediol in all concentrations and in all combinations (with BG and/or glycerol) increased skin hydration and improved skin barrier function 15 min, 2 and 8 h after application. Glycerol increased the hydration performance of 1,3-propanediol. The application of 1,3-propanediol at a concentration of 15%, either alone or in combination with other humectants, reduced the TEWL to a greater extent than lower concentrations of 1,3-propanediol. Furthermore, the addition of glycerol to 1,3-propanediol 15% improved the skin barrier and reduced TEWL when compared with 1,3-propanediol alone and with the combination of 1,3-propanediol + BG. CONCLUSION: The humectants significantly improved skin hydration and reduced TEWL throughout the 8-h time course. The increase in 1,3-propanediol concentration, as well as its combination with glycerol, provided a greater benefit to the skin, improving both hydration and the skin barrier function.

OBJECTIF: Cette étude visait à évaluer l'effet sur l'hydratation de la peau et la fonction de barrière cutanée du 1,3-propanediol à différentes concentrations (5 %, 10 % ou 15 %), appliqué seul ou en association avec du butylène glycol (5 %) et/ou du glycérol (5 %). Les mesures ont été effectuées à l'aide de la capacitance pour déterminer l'hydratation de la peau et les taux de perte d'eau transépidermique (Trans Epidermal Water Loss, TEWL) pour évaluer la fonction de barrière cutanée. MÉTHODES: Au total, 30 sujets de sexe féminin en bonne santé ont participé à l'étude. Les mesures de la capacitance et de la TEWL ont été effectuées à plusieurs moments, y compris avant l'application, 15 minutes, 2 heures et 8 heures après l'application des produits humectant sur les avant-bras des sujets. Tous les sujets ont fourni un consentement éclairé écrit. RÉSULTATS: Le 1,3-propanediol, à toutes les concentrations et dans toutes les associations (avec le butylène glycol et/ou le glycérol), a augmenté l'hydratation de la peau et amélioré la fonction de barrière cutanée à 15 minutes, 2 heures et 8 heures après l'application. Le glycérol a augmenté les performances d'hydratation du 1,3-propanediol. L'application de 1,3-propanediol à une concentration de 15 %, seul ou en association avec d'autres produits humectant, a réduit la TEWL dans une plus grande mesure que des concentrations inférieures de 1,3-propanediol. En outre, l'ajout de glycérol au 1,3-propanediol 15 % a amélioré la barrière cutanée et réduit la TEWL par rapport au 1,3-propanediol seul et à l'association 1,3-propanediol + butylène glycol. CONCLUSION: Les produits humectant ont significativement amélioré l'hydratation de la peau et réduit la TEWL tout au long des 8 heures. L'augmentation de la concentration de 1,3-propanediol, ainsi que son association avec le glycérol, ont apporté un plus grand bénéfice à la peau, améliorant à la fois l'hydratation et la fonction de barrière cutanée.

The use of Lentilactobacillus buchneri PJB1 and Lactiplantibacillus plantarum MTD1 on the ensiling of whole-plant corn silage, snaplage, and high-moisture corn.

Experiments were conducted over a 3-yr period to evaluate the effects of bacterial inoculants on the fermentation profile and aerobic stability of whole-plant corn silage (WPC), snaplage (SNA), and high-moisture corn (HMC). Whole-plant corn was inoculated with Lentilactobacillus buchneri PJB1 in combination with Lactiplantibacillus plantarum MTD1 or with Lpb. plantarum alone (experiments 1 and 2). Snaplage (experiment 3) and HMC (experiments 4 and 5) were inoculated with Len. buchneri in combination with Lpb. plantarum or with Len. buchneri alone. After inoculation, the feedstuffs were ensiled in 7.57-L silos and stored at 21 ± 2°C for 30 or 90 d. In experiment 5, silage was subjected to air stress for 2 h every 2 wk through 42 d and then for 2 h/wk until 90 d and had samples analyzed for their bacterial community composition by metagenomics. Overall, in all experiments, silages inoculated with Len. buchneri alone or in combination with Lpb. plantarum had more acetic acid and 1,2-propanediol and fewer yeasts than uninoculated silages. After 30 d of ensiling, inoculation with Len. buchneri alone or in combination with Lpb. plantarum did not affect the aerobic stability of SNA, but it slightly increased the stability of WPC and markedly improved the stability of HMC. After 90 d of ensiling, inoculation with Len. buchneri alone or in combination with Lpb. plantarum markedly improved the aerobic stability of WPC, SNA, and HMC. In experiment 5, inoculation increased the relative abundance (RA) of Lactobacillaceae and reduced the RA of Enterobacteriaceae and Leuconostocaceae in HMC at 30 and 90 d and the RA of Clostridiaceae in non-air-stressed HMC at 90 d. Air-stressed HMC inoculated with Len. buchneri had less lactic acid, more acetic acid and 1,2-propanediol, and markedly greater aerobic stability than uninoculated air-stressed HMC at 90 d. In conclusion, inoculation with Len. buchneri PJB1 alone or in combination with Lpb. plantarum MTD1 increased the production of acetic acid and 1,2-propanediol, inhibited yeasts development, and improved the aerobic stability of WPC, SNA, and HMC. In HMC, inoculation markedly improved aerobic stability as soon as after 30 d of ensiling, and after 90 d, inoculation improved stability even under air stress conditions.

Impact of vitamin B12 on rhamnose metabolism, stress defense and in-vitro virulence of Listeria monocytogenes.

Listeria monocytogenes is a facultative anaerobe which can cause a severe food-borne infection known as listeriosis. L. monocytogenes is capable of utilizing various nutrient sources including rhamnose, a naturally occurring deoxy sugar abundant in foods. L. monocytogenes can degrade rhamnose into lactate, acetate and 1,2-propanediol. Our previous study showed that addition of vitamin B12 stimulated anaerobic growth of L. monocytogenes on rhamnose due to the activation of bacterial microcompartments for 1,2-propanediol utilization (pdu BMC) with concomitant production of propionate and propanol. Notably, anaerobic 1,2-propanediol metabolism has been linked to virulence of enteric pathogens including Salmonella spp. and L. monocytogenes. In this study we investigated the impact of B12 and BMC activation on i) aerobic and anerobic growth of L. monocytogenes on rhamnose and ii) the level of virulence. We observed B12-induced pdu BMC activation and growth stimulation only in anaerobically grown cells. Comparative Caco-2 virulence assays showed that these pdu BMC-induced cells have significantly higher translocation efficiency compared to non-induced cells (anaerobic growth without B12; aerobic growth with or without B12), while adhesion and invasion capacity is similar for all cells. Comparative proteome analysis showed specific and overlapping responses linked to metabolic shifts, activation of stress defense proteins and virulence factors, with RNA polymerase sigma factor SigL, teichoic acid export ATP-binding protein TagH, DNA repair and protection proteins, RadA and DPS, and glutathione synthase GshAB, previously linked to activation of virulence response in L. monocytogenes, uniquely upregulated in anaerobically rhamnose grown pdu-induced cells. Our results shed light on possible effects of B12 on L. monocytogenes competitive fitness and virulence activation when utilizing rhamnose in anaerobic conditions encountered during transmission and the human intestine.