Biocidal Potential Research Articles

Cu(II) Biosorption and Synthesis of CuO Nanoparticles by Staphylococcus epidermidis CECT 4183: Evaluation of the Biocidal Effect

Copper contamination of natural waters is a global problem that affects ecosystems and public health, yet this metal is an essential micronutrient and has important applications. The efficacy of Staphylococcus epidermidis CECT 4183 as a Cu(II) biosorbent in synthetic solutions and its potential ability to synthesize CuO nanoparticles (CuO-NPs) from its cellular extract was investigated. In addition, the biocidal potential of the nanoparticles was evaluated against five microorganisms. Using response surface methodology, the optimal operating conditions were determined to be biomass dose, 0.2 g/L, and pH 5.5. Equilibrium tests were performed, and biosorption isotherms were obtained for four models with a maximum biosorption capacity of 48.14 mg/g for the Langmuir model. Different spectroscopic and microscopic techniques were used to determine the mechanisms involved in the biosorption process, which was dominated by surface physicochemical interactions with strong involvement of methyl, methylene, carbonyl, amino, and phosphate groups. The techniques also allowed for characterizing the obtained nanoparticles, which had a quasi-spherical morphology and an average size of 14 nm. Finally, biocidal tests showed that the CuO-NPs had a good inhibitory capacity for the microorganisms tested, with minimum inhibitory concentrations (MIC) between 62.5 and 500 µg/mL for bacteria and between 1000 and 2000 µg/mL for yeasts. S. epidermidis CECT 4183 showed good potential for Cu(II) bioremediation and for the synthesis of CuO-NPs with biocidal capacity. S. epidermidis CECT 4183 showed good potential for use in Cu(II) biosorption, and its cell extract presented a high capacity for the green synthesis of CuO-NPs, which at the same time turned out to be good biocidal agents.

An implementation framework for evaluating the biocidal potential of essential oils in controlling Fusarium wilt in spinach: from in vitro to in planta.

Fusarium wilt, caused by Fusarium oxysporum f. sp. spinaciae, causes a significant challenge on vegetative spinach and seed production. Addressing this issue necessitates continuous research focused on innovative treatments and protocols through comprehensive bioassays. Recent studies have highlighted the potential of plant-based compounds in controlling fungal diseases. The present work aims to conduct a series of experiments, encompassing both in vitro and in planta assessments, to investigate the biocontrol capabilities of different essential oils (EOs) at various application rates, with the ultimate goal of reducing the incidence of Fusarium wilt in spinach. The inhibitory effect of four plant EOs (marjoram, thyme, oregano, and tea tree) was initially assessed on the spore germination of five unknown Fusarium strains. The outcomes revealed diverse sensitivities of Fusarium strains to EOs, with thyme exhibiting the broadest inhibition, followed by oregano at the highest concentration (6.66 μL/mL) in most strains. The tested compounds displayed a diverse range of median effective dose (ED50) values (0.69 to 7.53 µL/mL), with thyme and oregano consistently showing lower ED50 values. The direct and indirect inhibitory impact of these compounds on Fusarium mycelial growth ranged from ~14% to ~100%, wherein thyme and oregano consistently exhibiting the highest effectiveness. Following the results of five distinct inoculation approaches and molecular identification, the highly pathogenic strain F-17536 (F. oxysporum f.sp. spinaciae) was chosen for Fusarium wilt assessment in spinach seedlings, employing two promising EO candidates through seed and soil treatments. Our findings indicate that colonized grain (CG) proved to be a convenient and optimal inoculation method for consistent Fusarium wilt assessment under greenhouse conditions. Seed treatments with thyme and oregano EOs consistently resulted in significantly better disease reduction rates, approximately 54% and 36% respectively, compared to soil treatments (P > 0.05). Notably, thyme, applied at 6.66 µL/mL, exhibited a favorable emergence rate (ERI), exceeding seven, in both treatments, emphasizing its potential for effective disease control in spinach seedlings without inducing phytotoxic effects. This study successfully transitions from in vitro to in planta experiments, highlighting the potential incorporation of EOs into integrated disease management for Fusarium wilt in spinach production.

Advances in silver nanoparticles: a comprehensive review on their potential as antimicrobial agents and their mechanisms of action elucidated by proteomics.

Nanoparticles play a crucial role in the field of nanotechnology, offering different properties due to their surface area attributed to their small size. Among them, silver nanoparticles (AgNPs) have attracted significant attention due to their antimicrobial properties, with applications that date back from ancient medicinal practices to contemporary commercial products containing ions or silver nanoparticles. AgNPs possess broad-spectrum biocidal potential against bacteria, fungi, viruses, and Mycobacterium, in addition to exhibiting synergistic effects when combined with certain antibiotics. The mechanisms underlying its antimicrobial action include the generation of oxygen-reactive species, damage to DNA, rupture of bacterial cell membranes and inhibition of protein synthesis. Recent studies have highlighted the effectiveness of AgNPs against various clinically relevant bacterial strains through their potential to combat antibiotic-resistant pathogens. This review investigates the proteomic mechanisms by which AgNPs exert their antimicrobial effects, with a special focus on their activity against planktonic bacteria and in biofilms. Furthermore, it discusses the biomedical applications of AgNPs and their potential non-preparation of antibiotic formulations, also addressing the issue of resistance to antibiotics.

Molecular Diversity from Longipinenes of Santolina viscosa Lag. through Acid Catalysis: Biocidal Activity.

The search for new compounds with biocidal potential was carried out, focusing on the longipinenes 1-7 from the plant species Santolina viscosa Lag. Compounds 1, 2, and 5 showed remarkable molecular diversity when treated in acidic reaction conditions. Protonic, Lewis, and heterogeneous compounds were used in the treatment. Three main models of reaction have been observed: isomerization of the double bond (8-10); rearrangements to longibornane-based skeleton (11-15) and ring-opening to himachalane-based skeleton (16-18). Secolongibornane aldehydes 23 and 24 were obtained after epoxide opening under the same reaction conditions. The elucidation of the structures of the new compounds was carried out using spectroscopic data and was supported by computational theoretical calculations of 13C NMR spectra. Additionally, high-resolution mass spectrometry and single-crystal X-ray diffraction analysis were employed for certain compounds. Natural longipinenes 4-7, methyl esters 1-3 of corresponding natural carboxylic acids and the isomerized and derivatives compounds 8-19 exhibit moderate to high insecticidal activity against R. padi and M. persicae insects. Longipinene 5 shows potent inhibition against the root growth of the plants L. perenne and L. sativa, as well as compound 2 on the leaves of L. perenne. Furthermore, significant ixocidal and nematicidal activity was found for this latter compound.

In Vitro Exploration of Entomopathogenic Nematodes as Potential Biocontrol Agents of Brinjal Borer Leucinodes Orbonalis Guenée (Lepidoptera: Crambidae)

Leucinodes orbonalis is a potential pest of eggplant, commonly known as fruit and shoot borer. Owing to its devastating nature, chemical pesticides are frequently applied and insecticide pressure is significantly higher in developing nations. Keeping the current situation in mind the most effective and practical strategy for managing insect pests found in humid and subtropical environments is the bio-control. Entomopathogenic nematodes, has been utilized against many pests for their effective management. Keeping in view the biocidal potential of entomopathogenic nematodes, the current study was planned to explore the biocidal potential of Steinernema and Heterorhabditis, two significant genera of entomopathogenic nematodes against L. orbonalis. White trap extraction technique was used to isolate nematodes from several insect larvae. Four discrete concentrations of entomopathogenic nematodes viz. 60, 90, 120, and 150 infective juveniles per larvae were applied on larval stages. The virulence trial was followed by completely randomized block design. Multiple comparisons showed that among both the tested nematodes H. bacteriophora induced significant 81.33% mortality corresponding to 150 IJs/larva after 72 h of exposure as compared to S. glaseri. In the view of current research, entomopathogenic nematodes are recommended to be used in integrated pest management program for the management of insect pests.

Genome Sequence Analysis of Native Xenorhabdus Strains Isolated from Entomopathogenic Nematodes in Argentina.

Entomopathogenic nematodes from the genus Steinernema (Nematoda: Steinernematidae) are capable of causing the rapid killing of insect hosts, facilitated by their association with symbiotic Gram-negative bacteria in the genus Xenorhabdus (Enterobacterales: Morganellaceae), positioning them as interesting candidate tools for the control of insect pests. In spite of this, only a limited number of species from this bacterial genus have been identified from their nematode hosts and their insecticidal properties documented. This study aimed to perform the genome sequence analysis of fourteen Xenorhabdus strains that were isolated from Steinernema nematodes in Argentina. All of the strains were found to be able of killing 7th instar larvae of Galleria mellonella (L.) (Lepidoptera: Pyralidae). Their sequenced genomes harbour 110 putative insecticidal proteins including Tc, Txp, Mcf, Pra/Prb and App homologs, plus other virulence factors such as putative nematocidal proteins, chitinases and secondary metabolite gene clusters for the synthesis of different bioactive compounds. Maximum-likelihood phylogenetic analysis plus average nucleotide identity calculations strongly suggested that three strains should be considered novel species. The species name for strains PSL and Reich (same species according to % ANI) is proposed as Xenorhabdus littoralis sp. nov., whereas strain 12 is proposed as Xenorhabdus santafensis sp. nov. In this work, we present a dual insight into the biocidal potential and diversity of the Xenorhabdus genus, demonstrated by different numbers of putative insecticidal genes and biosynthetic gene clusters, along with a fresh exploration of the species within this genus.

Biogenic synthesis of dopamine/carboxymethyl cellulose/TiO2 nanoparticles using Psidium guajavaleaf extract with enhanced antimicrobial and anticancer activities.

The green synthesis of metal oxide nanoparticles (NPs) has garnered considerable attention from researchers due to its utilization of eco-friendly solvents during synthesis and cost-effective approaches. This study focuses on the synthesis of titanium oxide (TiO2) and dopamine (DA) carboxymethyl cellulose (CMC)-doped TiO2 (DA/CMC/TiO2) NP using Psidium guajava leaf extract, while also investigating the structural, optical, and morphological and biocidal potential of the prepared NPs. Significantly larger zones of inhibition were observed for DA/CMC/TiO2 NPs compared to TiO2 against various pathogens. Moreover, the MTT assay was carried out to evaluate the anticancer activity of the prepared samples against MG-63 cells, and the results revealed that DA/CMC/TiO2 NPs exhibited significantly higher level of anticancer activity compared to TiO2. The experimental results demonstrated that DA/CMC/TiO2 NPs exhibited enhanced anticancer activity in a dose-dependent manner when compared to TiO2 NPs.

N-heterocyclic carbene based Bi-nuclear organoselenium compounds impart a mild biocidal potential compared to their ligands: Synthesis, characterization, computational studies

N-heterocyclic carbene (NHC) based compounds are remarkably known for astonishing biological potentials. Coordination of metal center with these compounds can substantially improve the biological potential for better efficacy. In this context, three binuclear azolium salts (L1-L3) and subsequent selenium adducts L1Se-L3Se were synthesized and assured through analytical techniques. Synthesized compounds were also simulated through computational approach and results were compared with experimental observations that also relatable with biological potentials. Synthesized compounds were screened against bacterial strains and interestingly, the studied compounds showed good antimicrobial potential with MIC values of 7.01, 10.7 and 10.5 µM for S. Aureus (gram positive bacteria) while 12.5, 11.75 and 14.5 µM against E. Coli (gram negative bacteria). The studied compounds showed good antioxidant activity to scavenge DPPH free radicals among which azolium salts were found better in antioxidant potential (IC50 5.75–6.55 µg/mL) than their respective selenium compounds (IC50 9.50–12.75 µg/mL). The hemolytic assay against red blood cells showed that ligands are least toxic comparative to their Se-adducts and can be further trialed for In Vivo studies.

Essential oils and extracts of plants as biocides against microorganisms isolated from the ruins of the Roman city of Conímbriga (Portugal)

Biodeterioration of monumental complexes is in large part due to the proliferation of various microorganisms that attack the physical–chemical structures of support materials. Various conservation and restoration interventions use commercial biocides of synthetic origin, which exhibit some human and environmental toxicity and sometimes side effects on support materials. The main objective of this work is the assessment of new biocides obtained from endemic Mediterranean plants, to be used in the preservation of cultural heritage with the goal of contributing to the sustainable use of ecosystems and to the development of Mediterranean local communities. The biocidal potential of essential oils (EOs) and solvent extracts (SEs) (ethanol and n-hexane) obtained from four plants were evaluated: Thymus mastichina (Tm), Mentha pulegium (Mp), Foeniculum vulgare (Fv), and Lavandula viridis (Lv). Microorganisms collected at an emblematic site of Portuguese cultural heritage, the ruins of the Roman city of Conímbriga, were used to evaluate the biocidal activity of the EOs and SEs. It can be concluded that (i) SEs did not exhibit fungicidal nor bactericidal activity, except for one fungus specie; (ii) biocidal activity of EOs depends on the microorganism specie. The EOs showed a relative average biocidal activity (when compared to the commercial biocide Biotin T (1% v/v)) of 64%, 32%, 30%, and 25% for Mp, Fv, Lv, and Tm. On carbonate rocks, the application of Fv and Mp EOs up to 3 layers do not promote significant color/tonality changes in the surface of the rock. And the application of three layers of Lv and four layers of Fv, Mp, and Lv OEs only promote the occurrence of blurs or stains (variation of tonality) on rocks that presents very low porosity. It can also be noted that the EO of Mp has the broadest spectrum of activity. The results allow considering the use of Mp, Fv, Lv, and Tm EOs as valid alternatives to commercial biocides, providing a prospective application in the field of green conservation of building heritage.

Evaluation of the susceptibility of Tritrichomonas foetus to extracts of Lantana camara (Verbenaceae) by flow cytometry.

Bovine Trichomonosis (BT), a sexually transmitted disease endemic in countries with extensive cattle farming and natural service, is one of the most common causes of reproductive failure. 5-nitroimidazoles and their derivatives are used for its treatment, mainly metronidazole. The emergence of drug resistance mechanisms and treatment failures raise the need to investigate the effectiveness of new active compounds that contribute to parasite control. In this regard, extracts of Lantana camara (Verbenacea) have shown high biocidal potential against isolates of Trypanosoma cruzi and Leishmania braziliensis in vitro assays, although their effect on Tritrichomonas foetus has not been demonstrated yet. The available information on in vitro susceptibility of trichomonicidal drugs comes from the use of a diversity of methodologies and criteria, especially the observation of parasite motility under the optical microscope to assess their viability. Recently, in our laboratory, the use of flow cytometry has been described for the first time as a rapid and efficient method to evaluate the viability of T. foetus against metronidazole. The present study aimed to evaluate the cytostatic effect of L. camara extracts against T. foetus isolates by flow cytometry. Under aerobic conditions, IC50 values of 22.60µg/mL were obtained on average. Under anaerobic conditions, the IC50 oscilated around 29.04µg/mL. The results obtained allowed describing the susceptibility exhibited by these protozoa, being a valuable information for the development of potential BT treatments.

Estimation of Biocidal Potential of Desert Phytopowders for the Management of Citrus Canker

Citrus is one of the most important fruit crops, throughout the world. It is a rich source of antioxidants and vitamin C. Citrus canker is a potential threat to its successful production. In current study, ten desert phytopowders including Xanthium strumarium, Dipterygium galucun, Leptadenia pyrotechnica, haloxylon recurvum, Suaeda fruticosa, Salsola baryosma, Citruluscolocynthis, Abutilon indicum, Aerva javanica, and Calotropis procera at three different concentrations (5.0, 7.5 and 10.0%) were evaluated under in vitro conditions against Xanthomonas citri pv. citri. Among all phytopowders, X. strumarium and S. fruticosa, showed maximum inhibition zone (40 mm) followed by S. baryosma(38.50 mm) C. colocynthis(37 mm), Abutilon indicum(34 mm), H. recurvum(32 mm), D. galucun (30.5 mm), A. javanica, (29.50 mm), L. pyrotechnica, (29.5 mm) and C. procera (28 mm) as compared to control. Then, effective phytopowders were applied under greenhouse and field conditions @ 5.0, 7.5 and 10.0% against citrus canker. Combination of X. strumarium + S. baryosma showed minimum disease severity (22%) followed by X. strumarium (26%), X. strumarium + S. fruticosa (27%), S. fruticosa (27%), X. strumarium + S. baryosma (27%), and S. baryosma (29%) as compared to control. While in field experiment, the combination of X. strumarium + S. fruticosa showed significant results with minimum disease severity (32%) followed by S. fruticosa + S. baryosma (32%), X. strumarium + S. baryosma (33%), S. baryosma (35%), X. strumarium (36%) and S. fruticosa (36%) as compared to control. It is concluded that application of X. strumarium + S. baryosma phytopowders will be helpful for farmers to combat citrus canker.

Peruvian plant resources as potential natural controllers of adult Aedes aegypti

Aedes aegypti is an important vector of tropical diseases like Dengue, Zika, Chikungunya, and Yellow Fever and affects mainly countries located in tropical and subtropical zones, including Peru. Synthetic insecticides are used to control this vector, but they also cause a residual effect on the environment, whereas the vector has developed resistance to these compounds, so there is a current need to search for new control alternatives, such as the use of abundant natural resources. Therefore, this work aimed to evaluate the biocidal activity of extracts and oils from Cymbopogum citratus, Rosmarinus officinalis, and Minthostachys mollis on adult Aedes aegypti, as well as to evaluate their quality parameters. Furthermore, the chemical profile of the three species was assessed by ultra-high-performance liquid chromatography coupled with mass spectrometry (LC-MS/MS). The results showed that the aqueous/ethanolic extracts and the essential oils from the three evaluated species presented a biocidal effect on adult A. aegypti. Regarding the analysis of the chemical profile, 15 compounds were identified in R. officinalis, while 29 compounds were identified from C. citratus and 30 compounds from M. mollis. Moreover, the extracts and oils presented quality parameters according to standards. In conclusion, the biocidal potential of the C. citratus, R. officinalis, and M. mollis on A. aegypti adults was reported so that they can be seen as a real natural alternative for the control of tropical diseases transmitted by this vector so that plant products are more eco-friendly and subject to lower resistance by target organisms.

Evaluation of the Cleaning Effect of Natural-Based Biocides: Application on Different Phototropic Biofilms Colonizing the Same Granite Wall

Natural derivatives, such as essential oils, are presented as an alternative to classical biocides to the treatment of biocolonization. Thus, in this work, the cleaning and biocidal potential of some natural derivatives towards two natural biofilms’ growth on the same granite wall, with different microbial composition, was evaluated. For this purpose, three essential oils (EOs) (from Origanum vulgare, Thymus vulgaris and Calamintha nepeta) and their main active principles (APs) (carvacrol, thymol and R-(+)-pulegone, respectively) were embedded in a hydrogel matrix, with different combinations of EOs and APs, in order to evaluate the synergistic action of different actives. For comparative purposes, pure hydrogel and a mechanical method (brushing) were also used. Colorimetric measurements and chlorophyll a fluorescence analyses were performed to evaluate the cleaning action of the treatments on the biofilms. Overall, the EOs and APs present in the hydrogel proved to be reliable treatments to limit natural biocolonization, with O. vulgare being one of the most effective treatments in combination with other compounds, due to the majority presence of carvacrol. Moreover, the effect of the different treatments strictly depended on the biofilm in question, as well as its ability to adhere to the substrate.

Biocidal Effect of Essential Oil of Verbena Officinalis on the Black Bean Aphis Fabae

The polyphagia and the great capacity of reproduction of the aphids, arouse the use of several control methods, among others, essential oils which constitute a good alternative to the fight chemical and one of the most explored pathways in the biological regulation of pests. The aim of the study is to estimate the insecticidal power of a bio product formulated from an oil bitter Verbena officinalis, on the reduction of fertility and population density of different biological forms of the black bean aphid Aphis fabae. The temporal effectiveness of the formulated bio product was estimated by evaluating the rates of residual populations Methods: The essential oil is extracted by hydrodistilation from Verbena officinalis leaves. After formulation, two doses were recommended (D=0.4g/l and DD=1g/l), and two treatment methods were used (foliar application and root absorption) on broad bean plants infested by Aphis fabae with the aim of highlight the insecticidal capacity of the essential oil of Verbena officinalis. The results showed that the two treatment modes have a very marked effect on the density of Aphis fabae where the dose parameter has little influence on the aphicidal activity of the essential oil of Verbena officinalis. On the other hand, the treatment by root absorption acts more on the residual populations and the fecundity of the black bean aphid compared to foliar application, the Biocidal potential of which is accentuated with increasing doses. The formulation has optimized the effectiveness of the essential oil of Verbena officinalis, which resulted in its high toxicity, the most effective root application of which.

Sustainable Antibacterial Activity of Polyamide Fabrics Containing ZnO Nanoparticles.

In this study, we present an unprecedented study on the influence of parameters such as dyeing, softening, and number of washes on the maintenance of the antibacterial activity of polyamide fabrics containing zinc oxide nanoparticles (ZnO NPs) impregnated by a simple and easy-to-scale technique. ZnO NPs were synthesized by the sol-gel method at different reaction times (1, 3, and 24 h), followed by surface modification with (3-glycidyloxypropyl)trimethoxysilane (GPTMS) and water dispersion. The reaction times of ZnO NP synthesis were modified to evaluate their influence on particle size and antibacterial activity after impregnation in fabrics. The presence of ZnO NPs in fabrics was observed by different techniques such as X-ray diffraction, infrared vibrational spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The mean diameter values of the ZnO NPs calculated in this work from different techniques remained at 5 nm regardless of the reaction time revealing the efficient control of the nanoparticle size, important for desired applications as ZnO NPs smaller than 10 nm show improved antibacterial activity. The antibacterial activity of fabrics containing ZnO NPs indicated that polyamide fabrics after impregnation with ZnO NPs synthetized have great and similar biocidal potential against Staphylococcus aureus and Escherichia coli both with and without the presence of a fabric softener or a dye. The antibacterial behavior of the different polyamide fabrics remained after 10 and 20 washing cycles. The results shown in this study demonstrated the possibility of obtaining polyamide fabrics containing ZnO NPs with the antibacterial activity resistant to chemical treatments used by industries as a softener or a dye. The results also reveal the maintenance of the antimicrobial activity of fabrics after several washing cycles. The reaction time of 1 for the production of ZnO NPs and the versatility of polyamide fabrics allow their application in different environments to control microbial infections.

Electrospun alginate mats embedding silver nanoparticles with bioactive properties

Polysaccharide-based composites embedding silver nanoparticles (AgNPs) represent a promising alternative to common antimicrobial materials because of the effective, broad-spectrum biocidal properties of AgNPs combined with the biocompatibility and environmental safety of the naturally occurring polymeric component. In this work, AgNPs stabilized with alginate chains (Alg@AgNPs) were successfully synthesized in situ within the polysaccharide solution through a wet chemical approach carried out at different concentrations of the silver salt precursor. Once obtained, the aqueous suspensions were electrospun to prepare non-woven membranes, showing a homogeneous nanostructured texture (with fiber diameter between 100 and 150 nm), which was found to be influenced by the size (between 20 and 35 nm) of the embedded metal nanoparticles.The biocidal potential of the nanocomposite mats was preliminarily tested against Gram-negative E. coli. The results showed that the antimicrobial response of the investigated samples occurred within a day of incubation and can be observed for AgNPs content in the polysaccharide fibers far below the nanomolar regime.

Unsymmetrical Ni(II) Schiff base complex: Synthesis, spectral characterization, crystal structure analysis, Hirshfeld surface investigation, theoretical studies, and antibacterial activity

A new nickel(II) complex (NiLUns) is synthesized by the reaction of unsymmetrical tetradentate salophen-based Schiff base (H2LUns) with Ni(CH3COO)2.4H2O. The different techniques, like elemental analysis (C, H, and N), FT-IR, UV-Vis, and NMR (1H & 13C), were used for structural elucidation of the H2LUns and NiLUns complex. The crystal structure of the nickel complex was studied in detail with the help of the X-ray diffraction technique. It was revealed from the diffraction data that the ligand chelates the Ni(II) ion by using its ONNO set of donor sites and forms a square planar geometry. The different types of strong as well as weak intermolecular interactions were explored with the help of Hirshfeld surface investigation. The theoretical parameters of the optimized structures were calculated by the DFT employing the B3LYP/Def2-TZVP level of theory. Furthermore, the synthesized NiLUns complex was screened against four different bacterial strains to evaluate its biocidal potential, which revealed that metal chelate is slightly more active than the free ligand. The synthesized NiLUns complex is novel concerning its spectroscopic analysis, diffraction studies, theoretical investigation, and antibacterial screening.

Xanthomonadin mediated synthesis of biocidal and photo-protective silver nanoparticles (XP-AgNPs)

Nanoparticles have drawn significant attention in recent years, owing to their unique electrical, optical, biocidal, and catalytic properties. The present study reports an environment friendly, green approach for silver nanoparticles (AgNPs) synthesis using bacterial yellow color pigment, xanthomonadin (XP) derived from Xanthomonas sp. After exposing the reaction mixture to sunlight, a visible colour shift and spectrophotometric measurement proved that nanosized silver particles (XP-AgNPs) were being synthesized by xanthomonadin. The size of XP–AgNPs was in the range between 30 and 100 nm, with the spherical shaped particles. The XP–AgNPs showed excellent biocidal activity against representative Gram positive and Gram negative organisms i.e. Staphylococcus aureus, B. subtilis and Pseudomonas aeruginosa, Escherichia coli. In addition, using standard assays, the photo-protecting/SPF enhancement of commercial sunscreens and DPPH radical scavenging activity of XP, and XP-AgNPs were evaluated. As a result, adding 4 % w/w xanthomonadin in commercial sunscreens have original SPFs 4 and 10 increases by 271 % and 85.2 %, respectively. XP and XP-AgNPs showed significant antioxidant activities with the IC50 values of 46.21 µg/mL and 21.62 µg/mL, respectively. In conclusion, xanthomonadin mediated silver nanomaterial with photo protecting, antioxidant and biocidal potential has been reported.

Potential of Asparagopsis armata as a Biopesticide for Weed Control under an Invasive Seaweed Circular-Economy Framework.

Simple SummaryThe invasive seaweed Asparagopsis armata has the potential to be used as a biopesticide. The application of its exudate shows severe impacts on energetic and carotenoid metabolism and induces significant oxidative stress in a model weed. This points to the potential use of this macroalga as a resource for a biopesticide cocktail, for sustainable and eco-friendly weed control and as a substitute for the chemical pesticides widely used nowadays.Marine macroalgae have been increasingly targeted as a source of bioactive compounds to be used in several areas, such as biopesticides. When harvesting invasive species, such as Asparagopsis armata, for this purpose, there is a two-folded opportunity: acquiring these biomolecules from a low-cost resource and controlling its spreading and impacts. The secondary metabolites in this seaweed’s exudate have been shown to significantly impact the physiology of species in the ecosystems where it invades, indicating a possible biocidal potential. Considering this in the present work, an A. armata exudate cocktail was applied in the model weed Thellungiella halophila to evaluate its physiological impact and mode of action, addressing its potential use as a natural biocide. A. armata greatly affected the test plants’ physiology, namely, their photochemical energy transduction pathway (impairing light-harvesting and chemical energy production throughout the chloroplast electron transport chain), carotenoid metabolism and oxidative stress. These mechanisms of action are similar to the ones triggered when using the common chemical pesticides, highlighting the potential of the A. armata exudate cocktail as an eco-friendly biopesticide.

Inactivation of Multidrug-Resistant Salmonella Heidelberg Isolated from Pigs by Ozonated Water under Different Conditions

ABSTRACT Salmonella Heidelberg is frequently associated with diseases transmitted by food of animal origin, so that the cleaning and disinfection of pigs farms are important for the control of this pathogen. This research was aimed to test the biocidal potential of ozonated water in different concentrations for the inactivation of a Salmonella Heidelberg isolated from pigs. We analyzed the strain antibiotic sensitivity profile to 17 antimicrobials and exposed the strain to disinfectant and three different concentrations of ozonated water (0.5 mg/L, 2.4 mg/L, and 4.4 mg/L) for one, five, and 10 minutes, in presence and absence of organic matter (OM), and performed a quantitative assessment of the bacterial genomic DNA. Salmonella Heidelberg was characterized as multidrug-resistant. Ozonated water inhibited bacterial growth in the absence of OM after one minute, with changes in bacterial DNA concentration.