Pigment Prodigiosin Research Articles

Prodigiosin, a promising biocontrol agent against Thaumetopoea wilkinsoni (Tams, 1926) (Lepidoptera: Notodontidae)

Serratia marcescens Bizio (Enterobacteriaceae: Serratia) is an entomopathogenic bacterium that produces hydrolytic enzymes and toxins. It also produces a pigment with various biological properties called prodigiosin. The study was conducted at Bilecik Seyh Edebali University in 2023. In this study, the effects of medium, incubation temperature and time on the process of prodigiosin production by S. marcescens strain Se9 and the extraction efficiency of different solvents were optimized for the first time using the orthogonal Taguchi array design. The optimal yield of pigment was achieved by methanol extraction from bacteria grown in tyriptic soy broth medium at 30ºC for 96 hours. The yield of prodigiosin pigment was 83.4±1.7 mg/L in the validation experiment conducted under the optimum conditions determined. The insecticidal potential of pigment against the larvae of Thaumetopoea wilkinsoni (Tams, 1926) (Lepidoptera, Notodontidae) was demonstrated for the first time. While the mortality rate in larvae exposed to 1000 ppm of the pigment was only 40%, it was observed that doubling the applied concentration led to a significant increase in larval mortality, reaching 91%. The LC50 value of the pigment for the fourth larval stage of T. wilkinsoni was determined to be 1192 ppm. The study showed that the pigment prodigiosin may be a promising biocontrol agent for the control of T. wilkinsoni.

Serratia marcescens ATCC 274 increases production of the red pigment prodigiosin in response to Chi phage infection

Serratia marcescens is an opportunistic human pathogen that produces a vibrant red pigment called prodigiosin. Prodigiosin has implications in virulence of S. marcescens and promising clinical applications. We discovered that addition of the virulent flagellotropic bacteriophage χ (Chi) to a culture of S. marcescens stimulates a greater than fivefold overproduction of prodigiosin. Active phage infection is required for the effect, as a χ-resistant strain lacking flagella does not respond to phage presence. Via a reporter fusion assay, we have determined that the addition of a χ-induced S. marcescens cell lysate to an uninfected culture causes a threefold increase in transcription of the pig operon, containing genes essential for pigment biosynthesis. Replacement of the pig promoter with a constitutive promoter abolished the pigmentation increase, indicating that regulatory elements present in the pig promoter likely mediate the phenomenon. We hypothesize that S. marcescens detects the threat of phage-mediated cell death and reacts by producing prodigiosin as a stress response. Our findings are of clinical significance for two main reasons: (i) elucidating complex phage-host interactions is crucial for development of therapeutic phage treatments, and (ii) overproduction of prodigiosin in response to phage could be exploited for its biosynthesis and use as a pharmaceutical.

Cytotoxic Effect of Biosynthesized Manganese Oxide Nanoparticles on Human Skin Squamous Carcinoma Cell Line (HSSCC) in vitro

The current study intended to biosynthesis of manganese oxide nanoparticles (MnO -NPs) depending on prodigiosin pigment as stabilizing and reducing agent. which produced from environmental isolate of Serratia marcescens . The study of the biosynthesis of MnO NPs was characterized by different techniques, such as ( UV-VIS, XRD, AFM, FE-SEM and FTIR). The results refer, the wavelength of biosynthesis of MnO NPs by using UV-VIS was (284 nm), the average volume was (45) nm). and image FE-SEM shows that the MnO- NPs mainly consists of nanosheets assembled in flower-like shape with different diameters. The cytotoxic effects of (MnO -NPs) on Human Skin Squamous Carcinoma Cell Line (HSSCC) was significant (p≤0.05) comparative with control viability 100%. Maximum effective concentration were 4000 μg/ml for 72hr exposure time which gave the highest inhibition rate 95% comparative with viability control 100%, but the minimum concentration was 3.9 μg/ml which induced proliferation of (HSSCC)cells. So when the exposure time and the concentration was increased, the inhibition rate was increased. Keywords:Serratia marcescens, Human skin squamous carcinoma cell line, cytotoxic effect, prodigiosin, MnO –NP.

Molecular insights into flavone-mediated quorum sensing interference: A novel strategy against Serratiamarcescens biofilm-induced antibiotic resistance"

Antibiotic resistance poses a significant challenge in modern medicine, urging the exploration of innovative approaches to combat bacterial infections. Biofilms, complex bacterial communities encased in a protective matrix, contribute to resistance by impeding antibiotic efficacy and promoting genetic exchange. Understanding biofilm dynamics is crucial for developing effective antimicrobial therapies against antibiotic resistance. This study explores the potential of flavone to combat biofilm-induced antibiotic resistance by employing in-vitro biochemical, cell biology, and Insilico (MD simulation), approaches. Flavone exhibited potent antibacterial effects with a low minimum inhibitory concentration by inducing intracellular reactive oxygen species. Flavones further inhibited the formation of biofilms by 50–60 % and disrupted the pre-formed biofilms by reducing the extracellular polysaccharide substance protective layer formed on the biofilm by 80 %. Quorum sensing (QS) plays a crucial role in bacterial pathogenicity and flavone significantly attenuated the production of QS-induced virulence factors like urease, protease, lipase, hemolysin and prodigiosin pigment in a dose-dependent manner. Further Insilico molecular docking studies along with molecular dynamic simulations run for 100 ns proved the stable binding affinity of flavone with QS-specific proteins which are crucial for biofilm formation. This study demonstrates the therapeutic potential of flavone to target QS-signaling pathway to combat S.marcescens biofilms.

Investigation of anti-adherence and antimicrobial properties of prodigiosin-functionalized bacterial cellulose membrane for biomedical applications

In this study, novel biomaterial that consisted entirely of bacterial products was developed with the approach of designing cost effective material for biomedical applications. With this aim, bacterial cellulose membranes (BCMs) which synthesized by Komagataeibacter intermedius were produced. Moreover, to impart antimicrobial properties to enhance the capacity of BCMs for biomedical usage, prodigiosin (PG) pigment of Serratia marcescens which presents wide range of antimicrobial activities was loaded to BCMs. Firstly, high yield of PG production was achieved, and then crude pigment was purified with silica gel column. The purified PG was characterized with thin layer chromatography and UV–visible spectrometry. The antimicrobial effect of the produced pigment on Gram-positive and negative bacteria and a yeast was investigated. The success of modification in PG-modified BCMs has been demonstrated by FTIR and SEM. Moreover, antimicrobial and antiadhesive ability of novel PG-BCMs were examined with disc diffusion and plate counting methods. As a result, it was established that PG-BCMs were able to inhibit the growth of all tested microorganisms. Furthermore, excellent antiadhesive effect was observed for the tested microorganisms with the inhibition rates of 82.05–96.25 %. Finally, cytotoxicity test with L929 cell line demonstrated that PG-BCM is biocompatible at a level that can be applied in in vivo studies.

Development of sustainable, eco-friendly antimicrobial finishing of cotton fabric using prodigiosin of Serratia marcescens SP1

Textile industries use synthetic colourants that often pollute soil, and water, which could be replaced with microbially derived pigment. The major aim of this study was to develop a textile fabric using microbially derived colourants that are eco-friendly in nature. A prodigiosin-producing bacterial strain was isolated and identified as Serratia marcescens SP1. The optimization of growth parameters revealed that yeast malt extract medium with pH of 7, temperature of 24 °C, and growth time of 3 days has maximum prodigiosin production. Further, the Rf value of 0.89 in TLC, UV visible absorption spectra of 534 nm, functional groups obtained in FTIR, a molecular weight of 322 D m/z in GC–MS, 81.13 % purity in HPLC, chemical shifts in NMR and an amorphous state in XRD confirmed the presence of prodigiosin pigment. It was found to have the highest antimicrobial activity against Staphylococcus aureus. Further, prodigiosin-imbibed fabrics possessed improved tensile strength, elongation, abrasion, crease recovery, stiffness, thickness, tearing strength, and bursting properties, confirming the stability and durability of the prodigiosin-coated fabric. The biodegradation ability of prodigiosin-coated fabric showed an increased degradation rate of 33.33 % compared to synthetic fabric. Overall, studies conferred the usage of prodigiosin to control infections on textile fabrics.

A conductive film produced by the supernatant from Serratia marcescens cultivation containing prodigiosin increases electricity generation in a microbial fuel cell

Although Serratia marcescens is known for its natural ability to produce the red pigment prodigiosin, it has been little explored as a biocatalyst in bioelectrochemical systems (BES). Here, we have employed an environmental S. marcescens isolate S734 as biocatalyst in a microbial fuel cell (MFC) anode to oxidize glycerol and to produce energy; we have evaluated how the anode behaves in three conditions: (i) as an abiotic electrode (FC-A); (ii) as a biotic electrode after S. marcescens biofilm growth (MFC-B); and (iii) as an abiotic electrode added with the supernatant containing prodigiosin (FC-P). Scanning electron microscopy and electrochemical measurements indicated that prodigiosin formed a conductive film over FC-P, which increased charge transfer by 424 times compared to FC-A. The maximum power density during the FC-P operation was 10.0 mW/m−2. Nevertheless, only in the presence of S. marcescens (MFC-B) was glycerol oxidized and electricity generated. Cyclic voltammetry indicated that the prodigiosin was the electrochemical active substance in the supernatant, and that its process was irreversible and controlled by adsorption. Electrochemical impedance spectroscopy confirmed that the prodigiosin-containing supernatant decreased the load resistance from 8396.3 Ω in FC-A to 58.10 Ω in FC-P. Genomic analysis showed that the prodigiosin biosynthesis gene cluster in strain S734 belonged to the Serratia 274 type, which contains pigA to pigN genes flanked by cueR and copA homologues. In conclusion, the supernatant produced by S. marcescens strain S734, containing prodigiosin could be explored as a green conductor in BES without further purification steps.

Development of a bacterial gene transcription activating strategy based on transcriptional activator positive feedback

IntroductionTranscription of biological nitrogen fixation (nif) genes is activated by the NifA protein which recognizes specific activating sequences upstream of σ54-dependent nif promoters. The large quantities of nitrogenase which can make up 20% of the total proteins in the cell indicates high transcription activating efficiency of NifA and high transcription level of nifHDK nitrogenase genes. ObjectivesDevelopment of an efficient gene transcription activating strategy in bacteria based on positive transcription regulatory proteins and their regulating DNA sequences. MethodsWe designed a highly efficient gene transcription activating strategy in which the nifA gene was placed directly downstream of its regulating sequences. The NifA protein binds its regulating sequences and stimulates transcription of itself and downstream genes. Overexpressed NifA causes transcription activation by positive reinforcement. ResultsWhen this gene transcription activating strategy was used to overexpress NifA in Pseudomonas stutzeri DSM4166 containing the nif gene cluster, the nitrogenase activity was increased by 368 folds which was 16 times higher than that obtained by nifA driven by the strongest endogenous constitutive promoter. When this strategy was used to activate transcription of exogenous biosynthetic genes for the plant auxin indole-3-acetic acid and the antitumor alkaloid pigment prodigiosin in DSM4166, both of them resulted in better performance than the strongest endogenous constitutive promoter and the highest reported productions in heterologous hosts to date. Finally, we demonstrated the universality of this strategy using the positive transcriptional regulator of the psp operon, PspF, in E. coli and the pathway-specific positive transcription regulator of the polyene antibiotic salinomycin biosynthesis, SlnR, in Streptomyces albus. ConclusionMany positive transcription regulatory proteins and their regulating DNA sequences have been identified in bacteria. The gene transcription activating strategy developed in this study will have broad applications in molecular biology and biotechnology.

Enhancing the prodigiosin pigment by adding Ag\\TiO2 synergism for antibacterial activity

To treat diseases brought on by drug-resistant microbes, researchers are presently using nanotechnology as one of the tools for studying the most obscure corners of medical sciences. The biological synthesis regarding Ag/TiO2 synergism in prodigiosin pigment was the primary focus of the presented work. Inhibitory and bactericidal properties of silver nanoparticles (AgNPs) have long been recognized. Titanium dioxide nanoparticles (TiO2 NPs) are employed as antibacterial agents in a variety of therapeutic sources. With using Nd:Yag laser (1064 nm), the composition has been synthesized by using environmentally friendly laser ablation in a liquid method. UV–visible spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) have been utilized for the analysis of the synthesized NPs. Optimal biosynthesis results showed a rise in the intensity of Surface Plasmon Resonance (SPR) bands of the NPs with shifting at 300 nm. TiO2 absorption peak at 230 nm. The results showed that the UV visible absorbance regarding prodigiosin pigment was at OD529. AgNPs/TiO2 exerted maximum antibacterial activity towards (Streptococcus, Bacillus subtilis, E. coli, Proteus vulgaris) Gram-negative and Gram-positive bacteria. The various Gram-negative and Gram-positive bacteria were subjected to various treatments (prodigiosin with Ag, prodigiosin pigment, and prodigiosin synergism with Ag/TiO2). The synergism is the best for antimicrobials than each one alone.

The Sustainable Bioactive Dyeing of Textiles: A Novel Strategy Using Bacterial Pigments, Natural Antibacterial Ingredients, and Deep Eutectic Solvents.

The textile industry stands as a prominent contributor to global environmental pollution, primarily attributable to its extensive reliance on synthetic dyes, hazardous components, and solvents throughout the textile dyeing and treatment processes. Consequently, the pursuit of sustainable textile solutions becomes imperative, aimed at replacing these environmentally unfriendly constituents with biobased and bioactive pigments, antibacterial agents, and, notably, natural solvents. Achieving this goal is a formidable yet indispensable challenge. In this study, the dyeing ability of the crude gel prodigiosin, produced by non-pathogenic bacteria Serratia plymuthica, was investigated on various multifiber fabrics at different conditions (temperature and pH) and by using salts and alternative mordants (the conventional Ferrous Sulphate (FeSO4) and a new bio-mordant, L-Cysteine (L-Cys)). Additionally, a novel gel-based Choline chloride (ChCl)/Lactic acid (LA) (1:2) deep eutectic solvent (DES) dyeing medium was studied to replace the organic solvents. Nylon fabrics dyed with 3.0% over the weight of the fiber (owf) L-Cys at pH = 8.3 had improved color fastness to washing, while the gel-based ChCl/LA (1:2) DES dyebath provided a better color fastness to light. Moreover, nylon fabrics under these conditions exhibited remarkable antimicrobial activity against Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa). In conclusion, the utilization of the crude gel-based prodigiosin pigment demonstrates a distinct advantage in dyeing textile materials, aligning with the growing consumer demand for more eco-friendly and sustainable products. Additionally, the application of the natural reducing agent L-Cys, previously untested as a bio-mordant, in conjunction with the use of gel-based DES as a dyeing medium, has showcased improved colorimetric and antibacterial properties when applied to nylon that is dyed with the crude gel prodigiosin pigment.

Isolation, Identification, and Antibacterial Properties of Prodigiosin, a Bioactive Product Produced by a New Serratia marcescens JSSCPM1 Strain: Exploring the Biosynthetic Gene Clusters of Serratia Species for Biological Applications.

Prodigiosin pigment has high medicinal value, so exploring this compound is a top priority. This report presents a prodigiosin bioactive compound isolated from Serratia marcescens JSSCPM1, a new strain. The purification process of this compound involves the application of different chromatographic methods, including UV-visible spectroscopy, high-performance liquid chromatography (HPLC), and liquid chromatography-mass spectrometry (LC/MS). Subsequent analysis was performed using nuclear magnetic resonance (NMR) to achieve a deeper understanding of the compound's structure. Finally, through a comprehensive review of the existing literature, the structural composition of the isolated bioactive compound was found to correspond to that of the well-known compound prodigiosin. The isolated prodigiosin compound was screened for antibacterial activity against both Gram-positive and Gram-negative bacteria. The compound inhibited the growth of Gram-negative bacterial strains compared with Gram-positive bacterial strains. It showed a maximum minimum inhibitory concentration against Escherichia coli NCIM 2065 at a 15.9 ± 0.31 μg/mL concentration. The potential binding capabilities between prodigiosin and the OmpF porin proteins (4GCS, 4GCP, and 4GCQ) were determined using in silico studies, which are generally the primary targets of different antibiotics. Comparative molecular docking analysis indicated that prodigiosin exhibits a good binding affinity toward these selected drug targets.

PtrA regulates prodigiosin synthesis and biological functions in Serratia marcescens FZSF02.

Serratia marcescens is a gram-negative bacterium that is able to produce many secondary metabolites, such as the prominent red pigment prodigiosin (PG). In this work, a ptrA-disrupted mutant strain with reduced PG production was selected from Tn5 transposon mutants. RT-qPCR results indicated that ptrA promoted elevated transcription of the pig gene cluster in S. marcescens FZSF02. Furthermore, we found that ptrA also controls several other important biological functions of S. marcescens, including swimming and swarming motilities, biofilm formation, hemolytic activity, and stress tolerance. In conclusion, this study demonstrates that ptrA is a PG synthesis-promoting factor in S. marcescens and provides a brief understanding of the regulatory mechanism of ptrA in S. marcescens cell motility and hemolytic activity.

Prodigiosin from Serratia rubidaea MJ 24 impedes Helicoverpa armigera development by the dysregulation of Juvenile hormone-dopamine system

Prodigiosin pigment is a secondary metabolite produced by many bacterial species and is known for its medicinal properties. A few of these prodigiosin-producing bacteria are also reported to be entomopathogenic. It is intriguing to unravel the role of prodigiosin in insecticidal activities and its mode of action. In this study, we have shown the production and characterization of prodigiosin from the Serratia rubidaea MJ 24 isolated from the soil of the Western Ghats, India. Further, we assessed the effect of this pigment on the lepidopteran agricultural pest, Helicoverpa armigera. Prodigiosin-fed H. armigera indicated defective development of insect growth upon treatment. Due to defective early development, about 50% mortality and 40% reduction in body weight were observed in insects fed on a 500 ppm prodigiosin-containing diet. The transcriptomic analysis of these insects indicated significant dysregulation of Juvenile hormone synthesis and response related genes. In addition, dopamine related processes and their resultant melanization and sclerotization processes were also found to be affected. The changes in the expression levels of the key transcripts were further validated using real-time quantitative PCR. The metabolome data confirmed the developmental dysregulation of precursors and products of differentially regulated genes due to prodigiosin. Therefore, the corroborated data suggests that prodigiosin majorly affects H. armigera development through dysregulation of the Juvenile hormone-dopamine system and can be considered as a bioactive scaffold to design insect-pest management compounds. This study provides the first report of in-depth analysis of insecticidal system dynamics in H. armigera insects upon prodigiosin feeding via gene expression and metabolic change via omics approach.

Genomic and phenotypic characterization of a red-pigmented strain of Massilia frigida isolated from an Antarctic microbial mat.

The McMurdo Dry Valleys of Antarctica experience a range of selective pressures, including extreme seasonal variation in temperature, water and nutrient availability, and UV radiation. Microbial mats in this ecosystem harbor dense concentrations of biomass in an otherwise desolate environment. Microbial inhabitants must mitigate these selective pressures via specialized enzymes, changes to the cellular envelope, and the production of secondary metabolites, such as pigments and osmoprotectants. Here, we describe the isolation and characterization of a Gram-negative, rod-shaped, motile, red-pigmented bacterium, strain DJPM01, from a microbial mat within the Don Juan Pond Basin of Wright Valley. Analysis of strain DJMP01's genome indicates it can be classified as a member of the Massilia frigida species. The genome contains several genes associated with cold and salt tolerance, including multiple RNA helicases, protein chaperones, and cation/proton antiporters. In addition, we identified 17 putative secondary metabolite gene clusters, including a number of nonribosomal peptides and ribosomally synthesized and post-translationally modified peptides (RiPPs), among others, and the biosynthesis pathway for the antimicrobial pigment prodigiosin. When cultivated on complex agar, multiple prodiginines, including the antibiotic prodigiosin, 2-methyl-3-propyl-prodiginine, 2-methyl-3-butyl-prodiginine, 2-methyl-3-heptyl-prodiginine, and cycloprodigiosin, were detected by LC-MS. Genome analyses of sequenced members of the Massilia genus indicates prodigiosin production is unique to Antarctic strains. UV-A radiation, an ecological stressor in the Antarctic, was found to significantly decrease the abundance of prodiginines produced by strain DJPM01. Genomic and phenotypic evidence indicates strain DJPM01 can respond to the ecological conditions of the DJP microbial mat, with prodiginines produced under a range of conditions, including extreme UV radiation.

Biosynthesis of Nio Nanoparticles Using Prodigiosin Pigment and its Evaluate of Antibacterial Activity Against Biofilm Producing MDR- Pseudomonas Aeruginosa

The entire investigation's focus was on the production of nickel oxide nanoparticles (NiONPs), using prodigiosin pigments produced by Serratia marcescens as a stabilizing and reducing agent. Nickel oxide nanoparticles are synthesized using nickel sulfate NiSO4 (10mg) with a concentration of prodigiosin (10g/100ml). Biosynthesized NiO nanoparticles have been characterized by using many techniques, such as (UV-Vis, AFM, XRD, FTIR, and FE-SEM). The AFM analysis revealed that NiONPs have an average diameter size of (41.77 mm), and the FE-SEM Image displays Spherical. Additionally, the effect of NiONPs with different concentrations on the bacteria Pseudomonas aeruginosa was measured and the inhibition zone reached to (29 mm). Biosynthesis of NiONPs using prodigiosin was shown to have promising activity as an antibacterial against the biofilm-producing Pseudomonas aeruginosa.

Antioxidant prodigiosin-producing cold-adapted Janthinobacterium sp. ERMR3:09 from a glacier moraine: Genomic elucidation of cold adaptation and pigment biosynthesis

Janthinobacterium from cold niches has been studied broadly for bioactive violacein production. However, reports on the atypical red-pigmented Janthinobacterium strains are shallow. The bioactive red prodigiosin pigment has immense pharmacological significance, including antioxidant, antimicrobial and anticancer potential. Here, we report the first complete genome of a prodigiosin-producing Janthinobacterium sp. ERMR3:09 from Sikkim Himalaya in an attempt to elucidate its cold adaptation and prodigiosin biosynthesis. Nanopore sequencing and Flye assembly of the ERMR3:09 genome resulted in a single contig of 6,262,330 bp size and 62.26% GC content. Phylogenomic analysis and genome indices indicate that ERMR3:09 is a potentially novel species of the genus Janthinobacterium. The multicopy cold-responsive genes and gene upregulation under cold stress denoted its cold adaptation mechanisms. Genome analysis identified the unique genes, gene cluster and pathway for prodigiosin biosynthesis in ERMR3:09. Considering the notable antioxidant activity, it can be the next powerhouse of bioactive prodigiosin production.

Industrial Applications of Red Pigment Prodigiosin Extracted from Serratia marcescens

Industrial Applications of Red Pigment Prodigiosin Extracted from Serratia marcescens

Prodigiosin Pigmentinin Tenebrio molitor (Coleoptera:Tenebrionidae) Üzerindeki İnsektisidal Aktivitesi

Microorganisms and their metabolites have the potential to provide a sustainable alternative to chemical insecticides. Serratia marcescens is an entomopathogenic bacterium that produces hydrolytic enzymes and toxins. It also produces a red pigment called prodigiosin, which has a variety of biological properties. In this study, the prodigiosin pigment was extracted from S. marcescens Se9 isolate with acidified ethanol and concentrated using a rotary evaporator. The insecticidal potential on larval and adult stages of Tenebrio molitor was then investigated. It was found that the mortality rate of larvae exposed to the lowest concentration (125 ppm) of crude pigment was 5%, while the mortality rate of larvae exposed to the highest concentration (2000 ppm) was 68%. The LC50 value of the crude pigment for the larval stage was determined to be 924 ppm. On the other hand, even at the highest pigment concentration (2000 ppm), only 30% mortality was observed in adults. The LC50 value of the crude pigment for the adult stage was determined to be 4570 ppm. It was determined that the pigment had a toxic effect on the pest, but the larval stage was more sensitive than the adult stage. The study showed that prodigiosin pigment appears to be a promising biocontrol agent for use against T. molitor.

Combating planktonic and biofilm growth of Serratia marcescens by repurposing ebselen.

The rising instances of multidrug-resistant pathogens are rapidly evolving into a global healthcare crisis. Identifying new ways of synthesis of antibiotics is both time-consuming and expensive. Repurposing existing drugs for the treatment of such antimicrobial-resistant pathogens has also been explored. In the current study, ebselen was screened for antibacterial and antibiofilm activity against Serratia marcescens. Various antibacterial studies such as minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill curves, intracellular reactive oxygen species (ROS) quantification, and colony-forming unit assays were performed. The antibiofilm potential was assayed by biofilm inhibition, cell surface hydrophobicity assay, eradication, quantification of extracellular DNA (eDNA), and extracellular polymeric substance (EPS) layer and scanning electron microscopy (SEM) analysis were performed. Anti-quorum sensing assay was validated by quantifying the virulence factors production. Further molecular docking of ebselen with two quorum sensing (QS) specific proteins was also carried out. Antibacterial susceptibility tests showed potent antimicrobial activity of ebselen against S. marcescens with MIC50 of 14μg/mL. Ebselen's ability to disturb the redox environment by inducing significant ROS generation led to bacterial death. It also showed concentration-dependent bactericidal activity as indicated by reduced bacterial growth and colony-forming unit propagation. Ebselen was also found to prevent biofilm attachment by altering the cell surface hydrophobicity while also being effective against preformed biofilms as validated by scanning electron microscopy (SEM) analysis. Additionally, ebselen showed reduced virulence factors like urease enzyme activity and prodigiosin pigment production indicating its promising anti-quorum sensing potential. Molecular docking analysis validated the strong binding of ebselen with QS-specific proteins (1Joe and PigG) with binding energies of - 6.6 and - 8.1kj/mol through hydrogen bonds and aromatic interactions. These results show that ebselen has potent antibiofilm potential that can be explored to identify treatment against bacterial infections.

Evaluation the efficiency of purified prodigiosin pigment from Serratia marcescens as antibiofilm formation agent against Candida spp. causing of denture stomatitis

An infection of the human oral cavity that is primarily fungal is called Candida-associated denture stomatitis. Erythema of the palate and alveolar ridges are symptoms of denture stomatitis, which is a persistent inflammatory condition of the mucosa supporting dentures. So that a red pigment made by Serratia marcescens and designated as prodigiosin was purified by silica gel column chromatography with a yield of 3.7 g/l after being extracted at higher concentrations using methanol with a yield of 3.3 g/l. Additionally, a UV scan of the pigment revealed that its highest absorbance occurred at 535 nm, and thin layer chromatography revealed that it had an Rf value of 0.86 when compared to standard. In cases of oral or denture stomatitis, Candida albicans was the dominating species followed by C. tropicalis, C. parapsilosis and C. dubliniensis, respectively. Checking for the development of biofilms by Candida spp. revealed that C. albicans and C. tropicalis produced biofilm but in different levels. The most effective source of biofilm production was C. albicans isolates. Candida species were prevented from forming biofilms by the purified prodigiosin. Candida albicans isolates had a greater proportion of biofilm inhibition, ranging from 63 to 82%. In contrast, the percentage of inhibition for isolates of C. tropicalis varied between 57 and 61%. Prodigiosin has a favorable advantage for potential usage in the dental sector since it stops and prevents the growth of biofilm.