Biocidal Effect Research Articles

Evaluation of antimicrobial activity of dosage forms based on Michurin's chokeberry leaves

Introduction. Recently, researchers have shown great interest in studying the phytochemical composition of Michurin's aronia leaves (Aronia × mitschurinii A.K. Skvortsov & Maitul) due to the significant content of such valuable biologcally active substances (BAS) as flavonoids, leucoanthocyanins and tannins of the condensed group. Considering the high potential astringent, capillary-protective and anti-inflammatory activity of the main target groups of the BAS of the studied raw materials, in the framework of the present study we have analysed the antimicrobial activity of aqueous-alcoholic liquid extracts of the medicinal forms from Michurin's chokeberry leaves. In our recent studies, we have also established the biocidal effect of the decoction in vitro at a dilution of 1 : 10 on the test system of infusoria Parametium caudatum under the damaging effect of sodium chloride solution in the test "Functional load".Aim. The purpose of the work was to determine the antimicrobial activity of aqueous-alcoholic liquid extraction dosage forms obtained from the leaves of chokeberry Michurin, in order to assess the prospects for creating medicinal herbal preparations (MHRP).Materials and methods. The object of the study were liquid extraction dosage forms, tincture (1 : 5) and liquid extract (1 : 1), obtained from dried leaves of Michurin's chokeberry using 60 % ethanol. The antimicrobial activity of the samples was determined by the double serial dilution method. Staphylococcus aureus, Bacillus cereus, Candida albicans, Escherichia coli, Pseudomonas aeruginosa strains were used as test cultures. The prediction of the main types of pharmacological activity by in silico method was carried out for the pre-identified components of the leaf polyphenolic complex – catechin, rutin and leucocyanidin – using PassOnline and Phyto4Health platform. The medicinal forms obtained were standardised in accordance with the requirements for tinc-tures and extracts of the State Pharmacopoeia XV edition.Results and discussion. The in silico screening of the main target groups of the BAS of the studied raw materials confirmed their high potential astringent and anti-inflammatory activity. The BAS complex of the liquid ex-tract of Michurin's chokeberry leaves in comparison with the tincture shows antimicrobial activity against Pseudomonas aeruginosa up to the 4th dilution and antifungal activity against Candida albicans up to the 6th dilution. In relation to such pathogenic microorganisms as Bacillus cereus and Staphylococcus aureus both tested dosage forms showed antimicrobial activity up to the 6th–7th dilution. The dosage form with a wider spectrum of antimicrobial activity is the liquid extract. In addition, the obtained dosage forms were standardized according to the requirements of the State Pharmacopoeia of the Russian Federation.Conclusion. The results of the evaluation of the antimicrobial activity of the obtained alcoholic dosage forms based on Michurin's chokeberry leaves (tincture and liquid extract), confirmed the prospects of creating herbal medicines, e.g. for external use in the complex therapy and prevention of diseases of the oral cavity in the form of rinses or applications.

Highly Stable Antitumor Silver-Lipid Nanoparticles Optimized for Targeted Therapy.

Silver nanoparticles (AgNPs) have a broad spectrum of biocidal effects, allowing also their antitumor application. To enhance bioavailability, minimize adverse effects and enable targeted drug delivery AgNPs may be encapsulated in liposomes. In this study we aimed to create highly stable and effective antitumor AgNP lipid formulations (LAgs). Uncapped and citrate-stabilized AgNPs were encapsulated by the lipid film hydration method using several phospholipid mixtures, followed by the essential removal of unencapsulated AgNPs by size exclusion chromatography (SEC). Purified LAgs were characterized by UV-VIS, DLS, XRD, ICP-MS, transmission electron microscopy (TEM) and glycerol-based density gradient centrifugation (DGC). Liposomal stability was assessed by carboxyfluorescein (CF) leakage, while antitumor effects of purified LAgs were tested in MTT, clonogenic and 3D spheroid invasion experiments. The presence of AgNPs inside SEC-purified liposomes was confirmed by TEM, XRD and ICP-MS. Encapsulation efficiency was estimated to be between 18.7 and 25.5%. Purified LAgs had higher density as compared to free AgNPs revealed by DGC, indicating that a considerable fraction of liposomes contained AgNPs. LAgs with PC/PG, PC/PG/SM/Chol, and in particular PC/PG/SM displayed the highest stability assessed by CF leakage, whereas high content of neutral or negatively charged phospholipids was destabilizing. As shown by MTT and colony formation assays, viability and survival of A375 and RPMI-7951 melanoma cells were severely impaired by LAgs at a higher or comparable level as caused by free AgNPs. Used as a non-tumor control, HEK293 cells were less vulnerable to LAgs as compared to free AgNPs. Finally, applying the most stable lipid composition, PC/PG/SM-LAg-c, and in part PC/PG/SM-LAg-u effectively inhibited a tissue-like invasion of melanoma spheroids. Altogether, highly stable purified LAg formulations were created, which effectively block survival, clonogenic potential and invasion of melanoma cells, therefore could be promising NP platforms for targeted tumor therapy.

Fabrication and characterization of chitosan-based bionanocomposite coating reinforced with TiO2 nanoparticles and carbon quantum dots for enhanced antimicrobial efficacy.

Polymer-based nanocomposite coatings that are enhanced with nanoparticles have gained recognition as effective materials for antibacterial purposes, providing improved durability and biocidal effectiveness. This research introduces an innovative chitosan-based polymer nanocomposite, enhanced with titanium oxide nanopowders and carbon quantum dots. The material was synthesized via the sol-gel process and applied to 316L stainless steel through dip-coating. Structural and morphological properties, including crystal structure, microstructure, elemental dispersion, particle size distribution, chemical composition, and surface morphology, were thoroughly characterized. The results demonstrated that carbon quantum dots and titanium oxide nanopowders were uniformly dispersed within the chitosan matrix, forming a homogeneous, non-agglomerated coating. The antibacterial efficacy of the synthesized samples against 7 different Gram-positive and Gram-negative bacteria was assessed through disk diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) tests. The results confirmed the antibacterial activity of synthesized samples against most of the bacterial pathogens tested but exhibited stronger antibacterial effects on Gram-negative bacteria compared to Gram-positive bacteria. The largest inhibition zones, measuring 21 mm and 16 mm, were observed for Pseudomonas and E. coli for titanium dioxide nanoparticles and the final nanocomposite, respectively. Additionally, the MIC and MBC values for all 7 bacteria were determined.

EVALUATION OF THE POSSIBILITY OF FLUSHING OF DRIP IRRIGATION SYSTEMS WITH ELECTROCHEMICALLY ACTIVATED LOW-CONCENTRATION SALT SOLUTIONS

The practice of using drip irrigation systems shows that contamination of drip outlets, including products of organic origin, is a serious threat to their reliable operation. In Ukraine, to combat such contamination, drip irrigation pipelines are flushed with environmentally hazardous 15% sodium hypochlorite AquaDoctor made in China. At the same time, there is evidence in the world practice of the possibility of effective use of environmentally friendly electrochemically activated low-concentrated saline solutions, in particular, anolyte, for such purposes. The analysis of the domestic market of disinfectants, bactericidal agents and antiseptics suggested that the anolyte "Crystal" produced by PE "Personnel Lux" (Kharkiv), which has a high biocidal effect. Kharkiv), which has a high biocidal activity at a mass total concentration of 0.1% of ADR, and electrochemically activated low-concentrated sodium hypochlorite "Secobren" with a hypochlorite content of up to 0.06% produced by "UKRTEK PRODUCT" LLC (Kyiv), which may have similar properties, can be used for flushing drip outlets. Laboratory and field studies have been conducted to determine the possibility of flushing drip irrigation pipelines with electrochemically activated low-concentrated saline solutions to remove contamination of drip irrigation outlets with products of organic origin. The study was conducted during the flushing of drip irrigation pipelines with integrated drippers from ASSIF (METZER, Israel) with AquaDoctor, Crystal and Secobren disinfectants. Laboratory studies were conducted in the laboratory of the Institute of Plant Industry and Mechanics of the National Academy of Agrarian Sciences of Ukraine, accredited in the UkrSEPRO system, and field studies were conducted on subsurface drip irrigation systems in Cherkasy and Kyiv regions. For flushing in the field, the "Forced installation of supply and mixing of PUPS" developed by IRRIGATOR UKRAINE LLC was used. The results of laboratory and field studies have shown that the washing capabilities of environmentally safe products "Kristal" and "Secobren" are comparable to those of environmentally hazardous hypochlorite "AquaDoctor". This makes it expedient to conduct further research to develop the technology of washing drip outlets depending on the nature and intensity of their pollution.

Thyme Essential Oil as a Potential Tool Against Common and Re-Emerging Foodborne Pathogens: Biocidal Effect on Bacterial Membrane Permeability.

Over the past decade, foodborne diseases have become a significant public health concern, affecting millions of people globally. Major pathogens like Salmonella spp., Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus contaminate food and cause several infections. This study investigates the potential of thyme essential oil (Thy-EO) as a natural antimicrobial agent against most common and re-emerging foodborne bacteria, including S. enterica, Yersinia enterocolitica, and L. monocytogenes. Preliminary tests provided qualitative evidence of Thy-EO's efficacy by evaluating its antibacterial activity through direct contact and vapor phase exposure. Then, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were defined to quantitatively evaluate the bacteriostatic and bactericidal effects of Thy-EO, revealing a strong inhibitory effect against S. enterica, Y. enterocolitica and L. monocytogenes. Additionally, Thy-EO exerted rapid bactericidal kinetics characterized by the disruption of bacterial cell membrane integrity over time. Results highlight Thy-EO's potential as an alternative antimicrobial agent, demonstrating that treatment with Thy-EO significantly and irreversibly affects the growth of the tested foodborne pathogens.

Exploring the dynamics of reactive oxygen species from CaviPlasma and their disinfection and degradation potential — the case of cyanobacteria and cyanotoxins

We investigated the production of highly reactive oxygen species (ROS) in solutions undergoing treatment using CaviPlasma (CP) technology. This technology combines plasma discharge with hydrodynamic cavitation. This study focused on factors such as pH, conductivity, presence of salts and organic matter affecting ROS formation and their stability in solutions. Depending on the used matrix, CP produces 450–580 µg L−1 s−1 of hydrogen peroxide and 1.9 µg L−1 s−1 of hydroxyl radicals dissolved in liquid. Using cyanobacteria and cyanotoxins as example, we proved that CP technology is a highly efficient method for destroying microorganisms and persistent toxins. The biocidal effect of the CP treatment was confirmed on two species of cyanobacteria, Synechococcus elongatus and Merismopedia minutissima. The effectiveness of the technology in degrading microcystins was also demonstrated. The potential of this technology is based on its high energy efficiency, G(H2O2) ≈ 10 g kWh−1 and G(O3) ≈ 0.03 g kWh−1 (in deionised water), realistic applicability with throughput rates (> 1 m3 h−1), and comparatively easy scalability system.

Oligostyrylbenzene Derivatives with Antiparasitic and Antibacterial Activity as Potent G-Quadruplex Ligands.

G-quadruplexes (G4s) are non-canonical secondary structures that play a crucial role in the regulation of genetic expression. This study explores the interaction between G4s and a small family of oligostyrylbenzene (OSB) derivatives, characterized by tris(styryl)benzene and tetrastyrylbenzene backbones, functionalized with either trimethylammonium or 1-methylpyridinium groups. Initially identified as DNA ligands, these OSB derivatives have now been recognized as potent G4 binders, surpassing in binding affinity commercially available ligands such as pyridostatin and displaying good selectivity for G4s over duplex DNA. Furthermore, OSB derivatives 1 and 2 demonstrated significant antiparasitic activity against bloodstream forms of T. brucei and extracellular L. major, with high selectivity indices when compared to MRC-5 healthy control cells. Derivatives 1 and 2 exhibited moderate biocidal effects against a range of Gram-positive and Gram-negative bacterial strains. Notably, a synergistic antibacterial effect was observed when these compounds were combined with traditional antibiotics, particularly against Acinetobacter baumannii, highlighting their potential utility in addressing drug-resistant bacterial infections. The differences in bioactivity among the OSB derivatives can be attributed to variations in cellular uptake, as proved by flow cytometry analysis. This suggests that the degree of cellular internalization plays a pivotal role in the observed antiparasitic and antibacterial efficacy.

Volatilomics of Capsicum pubescens Plants infested by Solenopsis geminata: Unraveling the Role of Oleic and Palmitic Acids in Plant-Fire Ant Interaction.

Solenopsis geminata is an aggressive pest of manzano pepper (Capsicum pubescens) crops. Herein, we report on the volatilomics profiling of manzano pepper plants obtained during S. geminata infestation by SPME-GC/MS. As a result, sixty-eight volatile organic compounds were identified from ants, non-infested plants, and infested plants, including terpenes, esters, steroids, aldehydes, phenylpropanoids, and fatty acids. As a remarkable finding, oleic and palmitic acids were the main compounds released during ant infestation. These fatty acids were evaluated as biocidal or repellent agents under in vitro and in situ conditions. From these experiments, the biocidal effect of palmitic acid was more potent (LC50, 0.97 mg/cm2) than that of oleic acid (LC50, 5.03 mg/cm2) on S. geminata workers. Nevertheless, only oleic acid had a repellent effect under in situ conditions (p < 0.01). Our results represent new insights into the role of both fatty acids in manzano pepper defense mechanisms.

Essential Oils and Essential Oil-Based Products Compared to Chemical Biocides Against Microbial Patinas on Stone Cultural Heritage

In recent years, attention has been paid to finding eco-friendly products that could represent an alternative for the chemicals usually used during conservation procedures. In the field of the devitalization of biological patinas, the most studied products are essential oils (EOs). Several works tested EOs in vitro on microorganisms isolated from stone artifacts but few applied these products on real artworks colonized by a complex patina. In the present work, the biocidal effect of two EOs (cinnamon bark and oregano) and two EO-based products (Biotersus and Essenzio) was compared to that of three chemical biocides commonly used in the conservation of stone artifacts (Biotin R1+R2, NewDes50, and Preventol RI50). The products were applied by brush in situ on a marble slab characterized by a green patina. The biocidal activity was evaluated by analyzing the chlorophyll fluorescence and quantifying ATP through biochemical tests. Furthermore, the products’ interference with stone was evaluated by colorimetric measures on sedimentary rock samples. The results indicate that chemical biocides exhibited biocidal activity of greater than 99.5% with a single application, while cinnamon oil (at a 1% concentration) and Essenzio required two applications to achieve the same level of efficacy. Conversely, oregano oil and Biotersus were not able to effectively reduce microorganism vitality, even with repeated applications.

Antimicrobial Activity of ZnS and ZnO-TOP Nanoparticles Againts Pathogenic Bacteria.

This study aims to synthesize ZnS nanoparticles (NPs) and investigate their biocidal effects, along with those of ZnO-Trioctylphosphine (ZnO-TOP) NPs, on various pathogenic microbes. The NPs were synthesized via the polyol method using the forced hydrolysis of zinc acetate. They were characterized by XRD and TEM. The average sizes of ZnS and ZnO-TOP are 3.63 nm and 16.28 nm, respectively. The antimicrobial activities were assessed using agar-well diffusion, minimum inhibitory concentration (MIC), and biofilm inhibition. The results showed that ZnS and ZnO-TOP NPs have potent antimicrobial activity against all tested pathogen microbes. A zone of maximum inhibition (ZMI) of 20±0.54 and 22±0.26 was observed in the case of ZnS for Acinetobacter baumannii and Candida albicans, respectively. For ZnO-TOP, a ZMI of 20±0.15 and 20±0.19 is obtained for Pseudomonas. aeruginosa ATCC 27853 and A. baumannii, respectively. Percentages of biofilm inhibition at 128 μg/ml were notably high for Enterococcus faecalis (96.83 % with ZnO-TOP and 91.17 % with ZnS) and Staphylococcus aureus (87.27 % with ZnO-TOP and 76.37 % with ZnS). The results suggest that ZnS and ZnO-TOP nanoparticles have promising potential as effective antimicrobial agents, especially against biofilm-forming pathogens, indicating their potential for future use in treating microbial infections.

Scalable Processing of Glass with Multi‐Functional Cu Coating

AbstractFunctional glass has been intensively studied as a future material with improved comfort, safety, and practicality across a variety of settings, including industrial, and residential environments. The integration of copper coatings on glass is noteworthy for its broad‐spectrum germicidal properties. When applied to frequently touched surfaces, this copper‐enhanced glass plays a crucial role in controlling infections, underscoring its significance in healthcare and public health contexts. Herein, an innovative approach for processing multifunctional copper coating on glass through atmospheric plasma spraying (APS) is introduced. The Cu coating demonstrates remarkable bactericidal efficiency against both Gram‐positive and Gram‐negative bacteria, achieving a 99.9% inhibition rate within 5 h. Moreover, the coating maintains its biocidal effectiveness for up to 3 days against these bacterial strains. The Cu coated glass also incorporates an electrical heating function. This feature allows the glass to increase its surface temperature by ≈7 °C with a minimal power load of 2V. The coating's transparency is variable and can be adjusted through the APS parameters, depending on the desired copper surface coverage. The combination of superior antibacterial properties and electrical heating capability makes the Cu coated glass as high‐performance material for medical applications, offering dual functions of infection control and temperature regulation.

PROSPECTIVE DIRECTIONS OF THE DEVELOPMENT OF BIOACTIVE GLASS FIBERS FOR MEDICAL APPLICATION

The urgency of the development and use of glass fibers for the creation of microfiber dressings for the treatment of chronic wounds in combat conditions has been determined. The availability of such materials is especially important in the conditions of hostilities, which are characterized by the need for quick resuscitation of the wounded and the provision of emergency aid on the battlefield. The use of such materials will save life, shorten the rehabilitation period, and speed up the recovery of the military and civilian population. An analysis of the scientific and technical literature on the composition and properties of bioactive glass fibers for medical use was carried out. The compositions and properties of glass fibers for various purposes were analyzed and their possibility of use in the development of bioactive glass fibers for medical use was established. The selection of the compositions of bioactive glass fibers with a prolonged biocidal effect for the rapid healing of wounds and the restoration of bone tissue is substantiated. The mechanism of action of biocidal components and boron ions in the composition of bioglasses on the ability to inhibit the negative effects of pathogenic microorganisms was analyzed. The use of boroaluminophosphate glass fibers for the manufacture of effective dressings for the treatment of wounds in crisis situations in combat conditions will increase the percentage of survival and reduce the duration of treatment due to the direct action of cations and anions of the materials in vivo. The main theoretical principles of the creation of bioactive boroaluminophosphate glass fibers, modified with group II metal cations, which will be characterized by the presence of a strengthened surface layer, and characterized at the same time by high biocompatibility, biocide with prolonged action and non-toxicity, have been determined. The introduction of domestically developed bioactive glass fibers into medical practice will significantly increase the competitiveness of domestic medical materials, as well as ensure defense capability and safety, and contribute to the stabilization of the market in the conditions of sustainable development of the state.

Variable sensitivity of clinical Candida auris strains to Biocides: implications for infection control in Healthcare Settings

PurposeCandida auris, a multidrug-resistant yeast, poses significant challenges in healthcare settings due to its ability to form biofilms and resistance to common disinfectants. Understanding its susceptibility to biocides used in hospital disinfection practices is crucial for infection control. We investigated the biocide sensitivity of eight clinical C. auris strains from different patients and one reference strain (CDC B11903) using the biocide activity tests.MethodsSpecies identification was confirmed through MALDI-TOF MS, while clade differentiation and phylogenetic classification were determined via whole-genome sequencing. Biofilm formation was assessed using the MTT assay. Antifungal susceptibilities were tested according to CLSI standards. The effectiveness of biocides, including chlorine, chlorhexidine, and benzalkonium chloride, was evaluated through broth microdilution following CLSI standards and quantitative suspension and carrier tests, following EN standards.ResultsAll clinical strains were identified as clade 1, and the reference strain as clade 4, with all exhibiting biofilm formation. Clade 1 strains showed resistance to fluconazole, with MIC values ranging from 8 to 32 µg/ml, while being susceptible to other antifungals. Broth microdilution MIC assays for biocides demonstrated that all strains exhibited resistance to benzalkonium chloride. Chlorine and chlorhexidine showed variable efficacy, dependent on concentration and environmental cleanliness. Alcohol-based hand sanitizers demonstrated effectiveness against C. auris from the first minute of application.ConclusionThe study highlights the variable susceptibility of C.auris to different biocides, underscoring the challenge in eradicating this pathogen from healthcare environments. Our findings advocate for the careful selection of disinfectants in hospital settings, emphasizing the need for high-concentration chlorine and chlorhexidine solutions to combat C. auris, even in especially clean environments.

The effect of biocide chloromethylisothiazolinone/methylisothiazolinone (CMIT/MIT) mixture on C2C12 muscle cell damage attributed to mitochondrial reactive oxygen species overproduction and autophagy activation

ABSTRACT The mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one (CMIT/MIT) is a biocide widely used as a preservative in various commercial products. This biocide has also been used as an active ingredient in humidifier disinfectants in South Korea, resulting in serious health effects among users. Recent evidence suggests that the underlying mechanism of CMIT/MIT-initiated toxicity might be associated with defects in mitochondrial functions. The aim of this study was to utilize the C2C12 skeletal muscle model to investigate the effects of CMIT/MIT on mitochondrial function and relevant molecular pathways associated with skeletal muscle dysfunction. Data demonstrated that exposure to CMIT/MIT during myogenic differentiation induced significant mitochondrial excess production of reactive oxygen species (ROS) and a decrease in intracellular ATP levels. Notably, CMIT/MIT significantly inhibited mitochondrial oxidative phosphorylation (Oxphos) and reduced mitochondrial mass at a lower concentration than the biocide amount, which diminished the viability of myotubes. CMIT/MIT induced activation of autophagy flux and decreased protein expression levels of myosin heavy chain (MHC). Taken together, CMIT/MIT exposure produced damage in C2C12 myotubes by impairing mitochondrial bioenergetics and activating autophagy. Our findings contribute to an increased understanding of the underlying mechanisms associated with CMIT/MIT-induced adverse skeletal muscle health effects.

Potentiality of Antibacterial Gels for the Prophylactic Coating of Hernia Repair Prosthetic Materials.

Prosthetic mesh infection constitutes one of the major postsurgical complications following abdominal hernia repair. Antibacterial coatings represent a prophylactic strategy to reduce the risk of infection. This study assessed the in vitro response of two antibacterial gels made of 1% carboxymethylcellulose (CMC) functionalized with an antiseptic (chlorhexidine, CHX) or an antibiotic (rifampicin, RIF), developed for the coating of polypropylene (PP) meshes for hernia repair. Fragments of a lightweight PP mesh (1 cm2) presoaked in the unloaded or drug-loaded CMC (0.05% CHX; 0.13 mg/mL RIF) were challenged with 106 CFU/mL Staphylococcus aureus (Sa) and methicillin-resistant S. aureus (MRSA). Agar diffusion tests, sonication, turbidimetry, crystal violet staining, scanning electron microscopy and cell viability assays (fibroblasts, mesothelial cells) were performed to evaluate the response of the gels. Both compounds-especially the RIF-loaded gel-exerted a biocidal effect against gram-positive bacteria, developing wide inhibition halos, precluding adhesion to the mesh surface, and hampering bacterial survival in culture. The antibiotic gel proved innocuous, while lower viability was found in cells exposed to the antiseptic (p < 0.05). Together with their fast, affordable, convenient processing and easy application, the results suggest the potential effectiveness of these drug-loaded CMC gels in providing meshes with an antibacterial coating exhibiting great biocide performance.

Functionalizing heavy metal contained incinerated sewage sludge ash in recycled glass-based alkali-activated materials for sewer environment

This study evaluates the performance of alkali-activated cement (AAC) mortars in an artificial sewage environment. The mortars, initially prepared with waste glass powder (GP) and ground granulated blast furnace slag (GGBS) in a 50:50 mass ratio, were modified by replacing 10 wt% of GGBS with incinerated sewage sludge ash (ISSA) with the goal of offering a biocidal effect. Comparisons were made with calcium aluminate cement (CAC), metakaolin (MK), and MK combined with zinc ferrite nanoparticles, each at a similar GGBS replacement level. The results showed that only incorporating CAC improved the strength development, achieving compressive and flexural strengths of 62.7 MPa and 7.4 MPa, respectively, at 28 days, while introducing ISSA or MK reduced the compressive strength to 47 MPa and flexural strength to 4.5 MPa. Although heavy metal ions from ISSA or zinc ferrite nanoparticles minimized biofilm thickness, they could not compensate for the reduced strength and increased alkalis leaching. Among all the tested mixtures, the 50GP40GGBS10CAC mixture exhibited superior biogenic acid resistance, possibly due to its Al-rich C-N-A-S-H gel phases (Ca/Si = 0.4, Na/Al = 0.8, Si/Al = 3.4) and refined pore structure (porosity = 3.4 %), making it the most microbial acid-resistant option for sewer rehabilitation.

Biocidal effect of some quinoa extracts against cotton leafworm insect

Biocidal effect of some quinoa extracts against cotton leafworm insect

Synthesis, Physicochemical Characterization, and Antimicrobial Evaluation of Halogen-Substituted Non-Metal Pyridine Schiff Bases

Four synthetic Schiff bases (PSB1 [(E)-2-(((4-aminopyridin-3-yl)imino)methyl)-4,6-dibromophenol], PSB2 [(E)-2-(((4-aminopyridin-3-yl)imino)methyl)-4,6-diiodophenol], PSB3 [(E)-2-(((4-aminopyridin-3-yl)imino)methyl)-4-iodophenol], and PSB4 [(E)-2-(((4-aminopyridin-3-yl)imino)methyl)-4-chloro-6-iodophenol]) were fully characterized. These compounds exhibit an intramolecular hydrogen bond between the hydroxyl group of the phenolic ring and the nitrogen of the azomethine group, contributing to their stability. Their antimicrobial activity was evaluated against various Gram-negative and Gram-positive bacteria, and it was found that the synthetic pyridine Schiff bases, as well as their precursors, showed no discernible antimicrobial effect on Gram-negative bacteria, including Salmonella Typhi (and mutant derivatives), Salmonella Typhimurium, Escherichia coli, and Morganella morganii. In contrast, a more pronounced biocidal effect against Gram-positive bacteria was found, including Bacillus subtilis, Streptococcus agalactiae, Streptococcus pyogenes, Enterococcus faecalis, Staphylococcus aureus, and Staphylococcus haemolyticus. Among the tested compounds, PSB1 and PSB2 were identified as the most effective against Gram-positive bacteria, with PSB2 showing the most potent biocidal effects. Although the presence of reactive oxygen species (ROS) was noted after treatment with PSB2, the primary mode of action for PSB2 does not appear to involve ROS generation. This conclusion is supported by the observation that antioxidant treatment with vitamin C only partially mitigated bacterial inhibition, indicating an alternative biocidal mechanism.

Applications of Plant Essential Oils in Pest Control and Their Encapsulation for Controlled Release: A Review

Essential oils (EOs) are volatile products derived from the secondary metabolism of plants with antioxidant, antimicrobial, and pesticidal properties. They have traditionally been used in medicine, cosmetics, and food additives. In agriculture, EOs stand out as natural alternatives for pest control, as they show biocidal, repellent, and antifeedant effects. However, they are highly volatile compounds and susceptible to oxidation, which has limited their use as pesticides. This has led to exploring micro- and nano-scale encapsulation to protect these compounds, improving their stability and allowing for a controlled release. Various encapsulation techniques exist, such as emulsification, ionic gelation, and complex coacervation. Nanoemulsions are useful in the food industry, while ionic gelation and complex coacervation offer high encapsulation efficiency. Materials such as chitosan, gelatin-gum-Arabic, and cyclodextrins are promising for agricultural applications, providing stability and the controlled release of EOs. Encapsulation technology is still under development but offers sustainable alternatives to conventional agrochemicals. This article reviews the potential of EOs in pest management and encapsulation techniques that enhance their efficacy.

Synergistic Interactions among Vacuum, Solar Heating, and UV Irradiation Enhance the Lethality of Interplanetary Space

A Planetary Atmospheric Chamber (PAC) was used to create simulations of interplanetary conditions to test the spore survival of three Bacillus spp. exposed to interacting conditions of vacuum (VAC), simulated solar heating (HEAT), and simulated solar ultraviolet irradiation (UV). Synergism was observed among the experimental factors for all three Bacillus spp. tested that suggested the increased lethality of HEAT and UV when concomitantly exposed to VAC. The most aggressive biocidal effects were observed for assays with VAC + HEAT + UV conditions run simultaneously over short time-steps. The results were used to predict the accumulation of extremely rapid Sterility Assurance Levels (SALs; def., −12 logs of bioburden reduction) measured in a few minutes to a few hours for external surfaces of interplanetary spacecraft. Furthermore, the results were extrapolated to predict that approx. 1 × 104 SAL exposures might be accumulated for external surfaces on the Europa Clipper spacecraft during a 3.5-year transit time between Venus (0.7 AU) and Mars (1.5 AU) during a series of Venus–Earth–Earth gravity assists (VEEGA trajectory) to Jovian space. The results are applicable to external spacecraft surfaces exposed to direct solar heating and UV irradiation during transits though the inner solar system.