Palmitic Acid Inhibits the Virulence Factors of Candida tropicalis: Biofilms, Cell Surface Hydrophobicity, Ergosterol Biosynthesis, and Enzymatic Activity

Quorum Quenching Approaches against Bacterial-Biofilm-Induced Antibiotic Resistance

With the widespread phenomenon of antibiotic resistance and the diffusion of multiple drug-resistant bacterial strains, enormous efforts are being conducted to identify suitable alternative agents against pathogenic microorganisms. Since an association between biofilm formation and antibiotic resistance phenotype has been observed, a promising strategy pursued in recent years focuses on controlling and preventing this formation by targeting and inhibiting the Quorum Sensing (QS) system, whose central role in biofilm has been extensively demonstrated. Therefore, the research and development of Quorum Quenching (QQ) compounds, which inhibit QS, has gradually attracted the attention of researchers and has become a new strategy for controlling harmful microorganisms. Among these, a number of both natural and synthetic compounds have been progressively identified as able to interrupt the intercellular communication within a microbial community and the adhesion to a surface, thus disintegrating mature/preformed biofilms. This review describes the role played by QS in the formation of bacterial biofilms and then focuses on the mechanisms of different natural and synthetic QS inhibitors (QSIs) exhibiting promising antibiofilm ability against Gram-positive and Gram-negative bacterial pathogens and on their applications as biocontrol strategies in various fields.

Chemical composition and antimicrobial activity of Cordiera myrciifolia leaves against pathogenic bacteria and fungi: Drug potentiation ability and inhibition of virulence

Cordiera myrciifolia is an abundant species in Northeast Brazil that presents metabolites of biological/therapeutic interest. From this perspective, the present study aimed to investigate the chemical constituents and evaluate the in vitro antimicrobial activity of hexane (HECM) and ethanolic (EECM) extracts of C. myrciifolia leaves. The extracts were analyzed by chromatographic techniques (GC and UPLC) coupled with mass spectrometry. The antimicrobial activity of the extracts and the extracts combined with conventional drugs was evaluated by microdilution. The in vitro effect of the treatments on Candida's morphological transition was verified through cultivation in humid chambers. In HECM, 11 constituents including fatty acids, and triterpenes, including phytosterols, alkanes, tocols, and primary alcohols were identified. Triterpenes represented >40% of the identified constituents, with Lupeol being the most representative. In EECM, 13 constituents were identified, of which eight belonged to the class of flavonoids. High antibacterial activity of HECM was detected against Escherichia coli and Staphylococcus aureus, with Minimum Inhibitory Concentrations of 8 and 16 μg/mL, respectively. The combined activity was more effective when combined with Norfloxacin and Imipenem. In anti-Candida activity, the IC50 of the extracts ranged from 36.6 to 129.1 μg/mL. There was potentiating effect when associated with Fluconazole. Both extracts inhibited the filamentous growth of C. tropicalis at a concentration of 512 μg/mL. C. myrciifolia extracts prove to be candidates for the development of new therapeutic formulations to treat bacterial and fungal infections.

Anti-biofilm activity of marine algae-derived bioactive compounds

A large number of microbial species tend to communicate and produce biofilm which causes numerous microbial infections, antibiotic resistance, and economic problems across different industries. Therefore, advanced anti-biofilms are required with novel attributes and targets, such as quorum sensing communication system. Meanwhile, quorum sensing inhibitors as promising anti-biofilm molecules result in the inhibition of particular phenotype expression blocking of cell-to-cell communication, which would be more acceptable than conventional strategies. Many natural products are identified as anti-biofilm agents from different plants, microorganisms, and marine extracts. Marine algae are promising sources of broadly novel compounds with anti-biofilm activity. Algae extracts and their metabolites such as sulfated polysaccharides (fucoidan), carotenoids (zeaxanthin and lutein), lipid and fatty acids (γ-linolenic acid and linoleic acid), and phlorotannins can inhibit the cell attachment, reduce the cell growth, interfere in quorum sensing pathway by blocking related enzymes, and disrupt extracellular polymeric substances. In this review, the mechanisms of biofilm formation, quorum sensing pathway, and recently identified marine algae natural products as anti-biofilm agents will be discussed.

Perception of the Biocontrol Potential and Palmitic Acid Biosynthesis Pathway of Bacillus subtilis H2 through Merging Genome Mining with Chemical Analysis

Bacillus has been widely studied for its potential to protect plants from pathogens. Here, we report the whole genome sequence of Bacillus subtilis H2, which was isolated from the tea garden soil of Guiyang Forest Park. Strain H2 showed a broad spectrum of antagonistic activities against many plant fungal pathogens and bacteria pathogens, including the rice blast fungus Magnaporthe oryzae, and showed a good field control effect against rice blast. The complete genome of B. subtilis H2 contained a 4,160,635-bp circular chromosome, with an average G + C content of 43.78%. Through the genome mining of strain H2, we identified 7 known antimicrobial compound biosynthetic gene clusters (BGCs) including sporulation killing factor, surfactin, bacillaene, fengycin, bacillibactin, subtilosin A, and bacilysin. Palmitic acid (PA), a secondary metabolite, was detected and identified in the H2 strain through genome mining analysis and gas chromatography-mass spectrometry (GC-MS). Additionally, we propose, for the first time, that the type II fatty acid synthesis (FAS) pathway in Bacillus is responsible for PA biosynthesis. This finding was confirmed by studying the antimicrobial activity of PA and conducting reverse transcription-quantitative polymerase chain reaction (RT-qPCR) experiments. We also identified numerous genes associated with plant-bacteria interactions in the H2 genome, including more than 94 colonization-related genes, more than 34 antimicrobial genes, and more than 13 plant growth-promoting genes. These findings contribute to our understanding of the biocontrol mechanisms of B. subtilis H2 and have potential applications in crop disease control.

Exploring the Fluconazole-Resistance Modifying Activity and Potential Mechanism of Action of Fixed Oil from Caryocar coriaceum Wittm. (Caryocaraceae) against Candida Species

The fixed oil from the inner mesocarp of Caryocar coriaceum Wittm. is used in the Chapada do Araripe region of Brazil for the treatment of genitourinary candidiasis. This study aimed to evaluate the chemical composition, antifungal activity, reduction of fungal virulence, and the preliminary toxicity of the fixed oil from the inner mesocarp of C. coriaceum tested against three Candida yeasts. The oil was characterized by gas chromatography (GC-MS and GC-FID). Antifungal activity was assessed using the serial microdilution method. Additionally, the potential of the oil as an enhancer of fluconazole action was tested at sub-inhibitory concentrations (MIC/8). The mechanism of action of C. coriaceum fixed oil was determined by evaluating the inhibition of morphological transition in Candida spp. The chemical composition of the fixed oil of C. coriaceum comprised both unsaturated and saturated fatty acids. Oleic (61 %) and palmitic (33 %) acids were the major constituents. Regarding its anti-Candida activity, the oil inhibited the growth of C. albicans (IC50 : 371 μg/mL) and C. tropicalis (IC50 : 830 μg/mL). Furthermore, the oil reversed the antifungal resistance of C. albicans and C. tropicalis, restoring the susceptibility to fluconazole and reducing their IC50 from 12.33 μg/mL and 362 μg/mL to 0.22 μg/mL and 13.93 μg/mL, respectively. The fixed oil of C. coriaceum completely inhibited the morphological transition of C. albicans and C. tropicalis at a concentration of 512 μg/mL, but exhibited limited low antifungal potential against C. krusei. The observed antifungal activity may be attributed to the overproduction of reactive oxygen species. Additionally, the oil showed no toxic effect on the Drosophila melanogaster in vivo model. The fixed oil from the inner mesocarp of C. coriaceum emerge as a strong candidate for the development of new pharmaceutical formulations to treat infections caused by Candida spp.

Exploring the efficacy of tryptone-stabilized silver nanoparticles against respiratory tract infection-causing bacteria: a study on planktonic and biofilm forms

Respiratory tract infections (RTIs) are a common cause of mortality and morbidity in the human population. The overuse of antibiotics to overcome such infections has led to antibiotic resistance. The emergence of multidrug resistant bacteria is necessitating the development of novel therapeutic techniques in order to avoid a major global clinical threat. Our study aims to investigate the potential of tryptone stabilised silver nanoparticles (Ts-AgNPs) on planktonic and biofilms produced byKlebsiella pneumoniae(K. pneumoniae)and Pseudomonas aeruginosa(P. aeruginosa). The MIC50of Ts-AgNPs was found to be as low as 1.7 μg ml-1and 2.7 μg ml-1forK. pneumoniae and P.aeruginosarespectively. Ts-AgNPs ability to alter redox environment by producing intracellular ROS, time-kill curves showing substantial decrease in the bacterial growth and significantly reduced colony forming units further validate its antimicrobial effect. The biofilm inhibition and eradication ability of Ts-AgNPs was found to be as high as 93% and 97% in both the tested organisms. A significant decrease in the eDNA and EPS quantity in Ts-AgNPs treated cells proved its ability to successfully distort the matrix and matured biofilms. Interestingly Ts-AgNPs also attenuated QS-induced virulence factors production. This study paves way to develop Ts-AgNPs as novel antibiotics against RTIs causing bacterial biofilms.

Update on fungal lipid biosynthesis inhibitors as antifungal agents

Fungal diseases today represent a world-wide problem. Poor hygiene and decreased immunity are the main reasons behind the manifestation of this disease. After COVID-19, an increase in the rate of fungal infection has been observed in different countries. Different classes of antifungal agents, such as polyenes, azoles, echinocandins, and anti-metabolites, as well as their combinations, are currently employed to treat fungal diseases; these drugs are effective but can cause some side effects and toxicities. Therefore, the identification and development of newer antifungal agents is a current need. The fungal cell comprises many lipids, such as ergosterol, phospholipids, and sphingolipids. Ergosterol is a sterol lipid that is only found in fungal cells. Various pathways synthesize all these lipids, and the activities of multiple enzymes govern these pathways. Inhibiting these enzymes will ultimately impede the lipid synthesis pathway, and this phenomenon could be a potential antifungal therapy. This review will discuss various lipid synthesis pathways and multiple antifungal agents identified as having fungal lipid synthesis inhibition activity. This review will identify novel compounds that can inhibit fungal lipid synthesis, permitting researchers to direct further deep pharmacological investigation and help develop drug delivery systems for such compounds.

BCp12/PLA combination: A novel antibacterial agent targeting Mur family, DNA gyrase and DHFR

The combination of natural antimicrobial peptide BCp12/phenyllatic acid (BCp12/PLA) presents a more efficient antibacterial effect, but its antibacterial mechanism remains unclear. This study studied the synergistic antibacterial mechanism of BCp12 and PLA against S. aureus. The results demonstrated that the BCp12/PLA combination presented a synergistic antibacterial effect against S. aureus, with a fractional inhibitory concentration of 0.05. Furthermore, flow cytometry and scanning electron microscope analysis revealed that BCp12 and PLA synergistically promoted cell membrane disruption compared with the group treated only with one compound, inducing structural cell damage and cytoplasmic leakage. In addition, fluorescence spectroscopy analysis suggested that BCp12 and PLA synergistically influenced genomic DNA. BCp12 and PLA targeted enzymes related to peptidoglycan and DNA synthesis and interacted by hydrogen bonding and hydrophobic interactions with mur enzymes (murC, murD, murE, murF, and murG), dihydrofolate reductase, and DNA gyrase. Additionally, the combined treatment successfully inhibited microbial reproduction in the storage of pasteurized milk, indicating that the combination of BCp12 and PLA can be used as a new preservative strategy in food systems. Overall, this study could provide potential strategies for preventing and controlling foodborne pathogens.

Eliciting transcriptomic and antioxidant defensive responses against Rhizoctonia root rot of sorghum using the endophyte Aspergillus oryzae YRA3

Environmental pollution due to the improper use of the chemical fungicides represents a vital ecological problem, which affects human and animal health, as well as the microbial biodiversity and abundance in the soil. In this study, an endophytic fungus Aspergillus oryzae YRA3, isolated from the wild plant Atractylis carduus (Forssk.) C.Chr, was tested for its biocontrol activity against Rhizoctonia root rot of sorghum. The antagonistic potential of A. oryzae YRA3 was tested against Rhizoctonia solani in vitro. A full inhibition in the growth of R. solani was recorded indicating a strong antagonistic potential for this endophyte. To investigate the chemical composition of its metabolites, GC/MS analysis was used and thirty-two compounds in its culture filtrate were identified. Among these metabolites, some compounds with an antifungal background were detected including palmitic acid, 2-heptanone, and 2,3-butanediol. To these antifungal metabolites the antagonistic activity of A. oryzae YRA3 can be attributed. In the greenhouse experiment, treating of the infected sorghum plants with A. oryzae YRA3 significantly reduced severity of the Rhizoctonia root rot by 73.4%. An upregulation of the defensive genes (JERF3), (POD) and (CHI II) was recorded in sorghum roots when were inoculated with A. oryzae YRA3. In addition, an increment in the activity of peroxidase and polyphenol oxidase, as well as the total phenolic content in the sorghum roots was also recorded. Furthermore, the results obtained from the greenhouse experiment revealed a growth-promoting effect for inoculating the sorghum plants with A. oryzae YRA3. It can be concluded that A. oryzae YRA3 can be a probable biological agent to control this disease in sorghum. However, its evaluation under field conditions is highly needed in the future studies.

Antifungal activity of Lysinibacillus macroides against toxigenic Aspergillus flavus and Fusarium proliferatum and analysis of its mycotoxin minimization potential

BACKGROUND

Toxigenic fungi (Aspergillus and Fusarium) and their metabolites represent the major cause of corn and corn-based products contamination and consequently lead to severe economic and health issues.

AIM

Our current study aimed to investigate the efficacy of using L. macroides Bac6 as a biological control agent against the toxigenic fungi; A. flavus f10 and F. proliferatum f30 and their mycotoxins.

RESULTS

The results illustrated that A. flavus f10 produced the aflatoxins AFB1 and AFG2 with concentrations of 21.239 and 13.593 ppb, respectively. While F. proliferatum f30 produced fumonisin B1 (9600 ppb). Furthermore, L. macroides showed a high potential for inhibition of toxigenic fungal growth using a dual culture method. F. proliferatum f30 and A. flavus f10 were found to be inhibited by a percentage of 80 and 62.5%, respectively. The results were confirmed using the scanning electron microscope. The antagonistic bacteria, L. macroides, showed chitinase productivity and activity of 26.45 U/L and 0.12 U/mL/min, respectively, which illustrates its potential application as a biocontrol agent. The GC-MS analysis revealed an abundance of Pyrrolo[1,2-a] pyrazine-1,4-dione, Hexahydro in the bacterial supernatant that exhibited antifungal characteristics. L. macroides had a significant reduction of AFB1 and AFG2 produced by A. flavus f10, recording 99.25% and 99% inhibition, respectively. It also showed strong inhibition of fumonisin B1 (90% inhibition) produced by F. proliferatum f30.

CONCLUSION

Thus, the current study is a prospective study evaluating for the first time the potential impact of L. macroides Bac6 against the toxigenic fungi and their toxins.

Unveiling the Potential of Algal Extracts as Promising Antibacterial and Antibiofilm Agents against Multidrug-Resistant Pseudomonas aeruginosa: In Vitro and In Silico Studies including Molecular Docking

Multidrug-resistant Pseudomonas aeruginosa poses a global challenge due to its virulence and biofilm-forming ability, leading to persistent infections. This study had a dual focus: first, it aimed to investigate the biofilm activity and antibiotic resistance profiles of Pseudomonas aeruginosa isolates obtained from a fish-rearing farm. Second, it explored the potential of algal extracts as effective antibacterial and antibiofilm agents. The study analyzed 23 isolates of P. aeruginosa from the farm, assessing antibiotic resistance and biofilm formation. The antimicrobial and antibiofilm activities of two algal extracts, Arthrospira platensis (cyanobacteria) acetone extract (AAE) and Polysiphonia scopulorum (Rhodophyta) methanol extract (PME), were tested individually and combined (COE). The effects on biofilm-related gene expression were examined. AAE, PME, and COE were evaluated for antimicrobial and antibiofilm properties. Biofilm-related gene expression was measured and the extracts were analyzed for physicochemical properties and toxicity. Most P. aeruginosa isolates (86.9%) were antibiotic-resistant and formed biofilms. AAE, PME, and COE displayed promising antibacterial and antibiofilm effects, with COE being particularly effective. COE reduced a key biofilm-related gene expression. The fatty acid content (56% in AAE and 34% in PME) correlated with the effects. Specific compounds, such as phytol, bromophenol, and dihydroxy benzaldehyde, contributed to the activities. The extracts showed favorable characteristics and interactions with FabZ protein amino acids. This study suggests the potential of algal extracts as antibacterial and antibiofilm agents against drug-resistant infections. Further exploration in clinical applications is warranted.

Evaluation of the polyphenolic profile of native Ecuadorian stingless bee honeys (Tribe: Meliponini) and their antibiofilm activity on susceptible and multidrug-resistant pathogens: An exploratory analysis

Biofilms are associated with infections that are resistant to conventional therapies, contributing to the antimicrobial resistance crisis. The need for alternative approaches against biofilms is well-known. Although natural products like stingless bee honeys (tribe: Meliponini) constitute an alternative treatment, much is still unknown. Our main goal was to evaluate the antibiofilm activity of stingless bee honey samples against multidrug-resistant (MDR) pathogens through biomass assays, fluorescence (cell count and viability), and scanning electron (structural composition) microscopy. We analyzed thirty-five honey samples at 15% (v/v) produced by ten different stingless bee species (Cephalotrigona sp., Melipona sp., M. cramptoni, M. fuscopilosa, M. grandis, M. indecisa, M. mimetica, M. nigrifacies, Scaptotrigona problanca, and Tetragonisca angustula) from five provinces of Ecuador (Tungurahua, Pastaza, El Oro, Los Ríos, and Loja) against 24-h biofilms of Staphylococcus aureus, Klebsiella pneumoniae, Candida albicans, and Candida tropicalis. The present honey set belonged to our previous study, where the samples were collected in 2018-2019 and their physicochemical parameters, chemical composition, mineral elements, and minimal inhibitory concentration (MIC) were screened. However, the polyphenolic profile and their antibiofilm activity on susceptible and multidrug-resistant pathogens were still unknown. According to polyphenolic profile of the honey samples, significant differences were observed according to their geographical origin in terms of the qualitative profiles. The five best honey samples (OR24.1, LR34, LO40, LO48, and LO53) belonging to S. problanca, Melipona sp., and M. indecisa were selected for further analysis due to their high biomass reduction values, identification of the stingless bee specimens, and previously reported physicochemical parameters. This subset of honey samples showed a range of 63-80% biofilm inhibition through biomass assays. Fluorescence microscopy (FM) analysis evidenced statistical log reduction in the cell count of honey-treated samples in all pathogens (P <0.05), except for S. aureus ATCC 25923. Concerning cell viability, C. tropicalis, K. pneumoniae ATCC 33495, and K. pneumoniae KPC significantly decreased (P <0.01) by 21.67, 25.69, and 45.62%, respectively. Finally, scanning electron microscopy (SEM) analysis demonstrated structural biofilm disruption through cell morphological parameters (such as area, size, and form). In relation to their polyphenolic profile, medioresinol was only found in the honey of Loja, while scopoletin, kaempferol, and quercetin were only identified in honey of Los Rios, and dihydrocaffeic and dihydroxyphenylacetic acids were only detected in honey of El Oro. All the five honey samples showed dihydrocoumaroylhexose, luteolin, and kaempferol rutinoside. To the authors' best knowledge, this is the first study to analyze stingless bees honey-treated biofilms of susceptible and/or MDR strains of S. aureus, K. pneumoniae, and Candida species.

The Heat Shock Transcription Factor HsfA Plays a Role in Membrane Lipids Biosynthesis Connecting Thermotolerance and Unsaturated Fatty Acid Metabolism in Aspergillus fumigatus

Thermotolerance is a remarkable virulence attribute of Aspergillus fumigatus, but the consequences of heat shock (HS) to the cell membrane of this fungus are unknown, although this structure is one of the first to detect changes in ambient temperature that imposes on the cell a prompt adaptative response. Under high-temperature stress, fungi trigger the HS response controlled by heat shock transcription factors, such as HsfA, which regulates the expression of heat shock proteins. In yeast, smaller amounts of phospholipids with unsaturated fatty acid (FA) chains are synthesized in response to HS, directly affecting plasma membrane composition. The addition of double bonds in saturated FA is catalyzed by Δ9-fatty acid desaturases, whose expression is temperature-modulated. However, the relationship between HS and saturated/unsaturated FA balance in membrane lipids of A. fumigatus in response to HS has not been investigated. Here, we found that HsfA responds to plasma membrane stress and has a role in sphingolipid and phospholipid unsaturated biosynthesis. In addition, we studied the A. fumigatus Δ9-fatty acid desaturase sdeA and discovered that this gene is essential and required for unsaturated FA biosynthesis, although it did not directly affect the total levels of phospholipids and sphingolipids. sdeA depletion significantly sensitizes mature A. fumigatus biofilms to caspofungin. Also, we demonstrate that hsfA controls sdeA expression, while SdeA and Hsp90 physically interact. Our results suggest that HsfA is required for the adaptation of the fungal plasma membrane to HS and point out a sharp relationship between thermotolerance and FA metabolism in A. fumigatus. IMPORTANCE Aspergillus fumigatus causes invasive pulmonary aspergillosis, a life-threatening infection accounting for high mortality rates in immunocompromised patients. The ability of this organism to grow at elevated temperatures is long recognized as an essential attribute for this mold to cause disease. A. fumigatus responds to heat stress by activating heat shock transcription factors and chaperones to orchestrate cellular responses that protect the fungus against damage caused by heat. Concomitantly, the cell membrane must adapt to heat and maintain physical and chemical properties such as the balance between saturated/unsaturated fatty acids. However, how A. fumigatus connects these two physiological responses is unclear. Here, we explain that HsfA affects the synthesis of complex membrane lipids such as phospholipids and sphingolipids and controls the enzyme SdeA, which produces monounsaturated fatty acids, raw material for membrane lipids. These findings suggest that forced dysregulation of saturated/unsaturated fatty acid balance might represent novel strategies for antifungal therapy.

Anti-Biofilm Activity of Phenyllactic Acid against Clinical Isolates of Fluconazole-Resistant Candida albicans

Commonly found colonizing the human microbiota, Candida albicans is a microorganism known for its ability to cause infections, mainly in the vulvovaginal region, and is responsible for 85% to 90% of vulvovaginal candidiasis (VVC) cases. The development of drug resistance in C. albicans isolates after long-term therapy with fluconazole is an important complication to solve and new therapeutic strategies are required to target this organism and its pathogenicity. In the present study, phenyllactic acid (PLA) an important broad-spectrum antimicrobial compound was investigated for its antifungal and antivirulence activities against clinical isolates of C. albicans. Previously characterized strains of C. albicans isolates from women with VVC and C. albicans ATCC90028 were used to evaluate the antimicrobial and time dependent killing assay activity of PLA showing a MIC 7.5 mg mL−1 and a complete reduction of viable Candida cells detected by killing kinetics after 4 h of treatment with PLA. Additionally, PLA significantly reduced the biomass and the metabolic activity of C. albicans biofilms and impaired biofilm formation also with changes in ERG11, ALS3, and HWP1 genes expression as detected by qPCR. PLA eradicated pre-formed biofilms as showed also with confocal laser scanning microscopy (CLSM) observations. Furthermore, the compound prolonged the survival rate of Galleria mellonella infected by C. albicans isolates. These results indicate that PLA is a promising candidate as novel and safe antifungal agents for the treatment of vulvovaginal candidiasis.

Metabolomics profiling of culture medium reveals association of methionine and vitamin B metabolisms with virulent phenotypes of clinical bloodstream-isolated Candida albicans

Candida albicans is a predominant species causing candidemia in hospitalized patients. This study aimed to investigate the association of culture medium metabolomic profiles with biofilm formation and invasion properties of clinical bloodstream-isolated C. albicans. A total of twelve isolates and two reference strains were identified by virulent phenotypes. Their susceptibility was determined by the microdilution method, following EUCAST guidelines. Biofilm formation was evaluated with metabolic activity, morphology and agglutinin-like sequence 3 (ALS3) mRNA expression. Invasion into the vascular endothelial EA.hy926 cells was determined by lactate dehydrogenase release and internalization assay. Their metabolomic profiles were assessed by high-resolution accurate-mass spectrometry (HRAMS). The results showed four different phenotypes of C. albicans: high-biofilm/invasive (50%), high-biofilm/non-invasive (7%), low-biofilm/invasive (36%) and low-biofilm/non-invasive (7%). The metabolomic profiles of the culture medium determined strong correlation of the virulent phenotypes and the alteration of metabolites in the methionine metabolism pathway, such as homocysteine, 5-methyltetrahydrofolate and S-adenosylmethioninamine. Moreover, thiamine and biotin levels were significantly increased in Isolate03, representative of a high-biofilm/invasive phenotype. These results suggest that methionine and vitamin B metabolism pathways might be influenced by their virulent phenotypes and pathogenic traits. Therefore, their metabolism pathways might be a potential target for reducing virulence of C. albicans bloodstream infections.

Novel Preclinical Study of Galloylquinic Acid Compounds from Copaifera lucens with Potent Antifungal Activity against Vaginal Candidiasis Induced in a Murine Model via Multitarget Modes of Action

Vaginal candidiasis is a medical condition characterized by the overgrowth of Candida spp. in the vaginal cavity with complex recurrent pathogenicity as well as tolerance to antifungal therapy and hence is awaiting more safe and effective treatments. This work aimed to assess the potential antifungal activity of galloylquinic acid compounds (GQAs) from Copaifera lucens leaves against vaginal Candida albicans. The antifungal susceptibility test was performed against 20 isolates of multidrug-resistant (MDR) C. albicans using agar diffusion and broth microdilution assays. The results showed that GQAs exhibited strong antagonistic activity against the test isolates, with inhibition zone diameters ranging from 26 to 38 mm and low MICs (1 to 16 μg/mL) as well as minimum fungicidal concentrations (2 to 32 μg/mL). The MTT [3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide] assay confirmed the safety of GQAs against the Vero cell line, showing a 50% inhibitory concentration (IC50) of 168.17 mg/mL. A marked difference in the growth pattern of the treated and untreated pathogens was also observed, where a concentration-dependent reduction in the growth rate occurred. Moreover, a pronounced fungicidal effect was demonstrated 6 h after treatment with 1× the minimum fungicidal concentration (MFC), as evidenced by time-kill assays, where the number of survivors was decreased a 6-fold. GQAs effectively inhibited and eradicated about 80% of C. albicans biofilm at 6 μg/mL and 32 μg/mL, respectively. Interestingly, GQAs disturbed the fungal membrane integrity, induced cell lysis, and reduced the virulence factors (proteinase and phospholipase) as well as the catalase activity. Moreover, the ergosterol content in the plasma membrane decreased in a concentration-dependent manner. Additionally, the altered mitochondrial membrane potential was associated with an increased release of cytochrome c from mitochondria to the cytosol, suggesting the initiation of early apoptosis in GQA-treated cells. Transcriptional analysis revealed that all test genes encoding virulence traits, including SAP1, PLB1, LIP1, HWP1, and ALS1, were markedly downregulated in GQA-treated cells compared to the control. The in vivo murine model of vaginal candidiasis further confirmed the therapeutic activity of GQAs (4 mg/kg of body weight) against C. albicans. This work comprehensively evaluated the antifungal, antivirulence, and antibiofilm activities of GQAs against C. albicans isolates using in vitro and in vivo models, providing molecular-level insights into the antifungal mechanism of action and experimental evidence that supports the potential use of GQAs for the treatment of vaginal candidiasis. IMPORTANCE Our work presents a new perspective on the potential use of GQAs as safe and highly effective phytochemicals against MDR C. albicans. This microorganism colonizes the human vaginal epithelium, causing vaginal candidiasis, a condition characterized by recurrent pathogenicity and tolerance to traditional antifungal therapy. Based on the results of in vitro tests, our study reports GQAs antifungal modes of action. These compounds exhibited an anticandidal effect by deactivating the fungal hydrolytic enzymes, reducing ergosterol content in the plasma membrane, altering the potential of the mitochondrial membrane, and inducing apoptosis. Additionally, GQAs showed high activity in eradicating the biofilm formed by the fungus via the downregulation of HWP1, ALS, SAP, PLB, and LIP genes, which are constitutively expressed in the biofilm. In an in vivo murine model of vaginal candidiasis, GQAs further demonstrated strong evidence of their effectiveness as an antifungal therapy. In this regard, our findings provide novel insights into the potential therapeutic use of these phytoactive molecules for vaginal candidiasis treatment.

Chemical Composition, Antifungal and Anti-Biofilm Activities of Volatile Fractions of Convolvulus althaeoides L. Roots from Tunisia

The antifungal drugs currently available and mostly used for the treatment of candidiasis exhibit the phenomena of toxicity and increasing resistance. In this context, plant materials might represent promising sources of antifungal agents. The aim of this study is to evaluate for the first time the chemical content of the volatile fractions (VFs) along with the antifungal and anti-biofilm of Convolvulus althaeoides L. roots. The chemical composition was determined by gas chromatography coupled to a flame ionization detector and mass spectrometry. In total, 73 and 86 chemical compounds were detected in the n-hexane (VF1) and chloroform (VF2) fractions, respectively. Analysis revealed the presence of four main compounds: n-hexadecenoic acid (29.77%), 4-vinyl guaiacol (12.2%), bis(2-ethylhexyl)-adipate (9.69%) and eicosane (3.98%) in the VF extracted by hexane (VF1). n-hexadecenoic acid (34.04%), benzyl alcohol (7.86%) and linoleic acid (7.30%) were the main compounds found in the VF extracted with chloroform (VF2). The antifungal minimum inhibitory concentrations (MICs) of the obtained fractions against Candida albicans, Candida glabrata and Candida tropicalis were determined by the micro-dilution technique and values against Candida spp. ranged from 0.87 to 3.5 mg/mL. The biofilm inhibitory concentrations (IBF) and sustained inhibition (BSI) assays on C. albicans, C. glabrata and C. tropicalis were also investigated. The VFs inhibited biofilm formation up to 0.87 mg/mL for C. albicans, up to 1.75 mg/mL against C. glabrata and up to 0.87 mg/mL against C. tropicalis. The obtained results highlighted the synergistic mechanism of the detected molecules in the prevention of candidosic biofilm formation.

Aspergillus flavus YRB2 from Thymelaea hirsuta (L.) Endl., a non-aflatoxigenic endophyte with ability to overexpress defense-related genes against Fusarium root rot of maize

Fusarium root rot, caused by Fusarium solani (Mart.) Sacc., represents one of the most damaging diseases of maize affecting plant growth and yield. In this study, the antagonistic potential of a non-aflatoxigenic endophytic Aspergillus flavus YRB2, isolated from Thymelaea hirsuta (L.) Endl., was tested against F. solani in vitro. In addition, its biocontrol activity against Fusarium root rot of maize was evaluated under greenhouse conditions. Its impacts on plant molecular, pathological, physiological, and growth levels were also studied. Results obtained revealed a potent antagonistic behavior for A. flavus YRB2 against F. solani in vitro, recording 80% growth inhibition. Seventeen secondary metabolites were detected in the n-hexane extract of A. flavus YRB2 filtered culture broth using GC-MS analysis. Among them, various antifungal secondary metabolites were produced, namely palmitic acid, α-linolenic acid, stearic acid, 2, 4-di-tert-butylphenol, diisobutyl phthalate, and heneicosane. In contrast, HPLC analysis showed that no aflatoxins (B1, B2, G1, and G2) were detected. Under greenhouse conditions, colonization of maize plants with A. flavus YRB2 exhibited a potential biocontrol activity against Fusarium root rot, recording 73.4% reduction in the disease severity. Triggering of transcriptional expression level of the defense-related genes JERF3 (7.2-fold), CHI II (8-fold), and POD (9.1-fold) was reported, indicating the inducing effect on the plant immunity. In addition, an increment in the antioxidant enzymes POD and PPO, and the total phenolic content in maize roots was also observed in response to this treatment. Moreover, a growth-promoting effect was also observed for colonization of maize plants with A. flavus YRB2. Based on the obtained data, we can conclude that A. flavus YRB2 may represent a promising biocontrol and growth-promoting agent for maize plants against Fusarium root rot. Nevertheless, field evaluation is highly requested before the use recommendation.

New Strategy for Inducing Resistance against Bacterial Wilt Disease Using an Avirulent Strain of Ralstonia solanacearum

Ralstonia solanacearum is one of the globally significant plant pathogens that infect a wide host range of economically important plants. A study was conducted to evaluate the hypothesis that an avirulent strain of R. solanacearum can act as a biocontrol mediator for managing potato bacterial wilt. Virulent R. solanacearum was isolated and identified (GenBank accession number; OP180100). The avirulent strain was obtained from the virulent strain through storage for 3 weeks until the development of deep red colonies. The virulent strain had higher lytic activity than the avirulent strain. Tubers' treatments by the avirulent strain of R. solanacearum, (supernatant, boiled supernatant, and dead cells) significantly reduced plant disease rating and increased the growth, physiological activities, and biomass of potato compared to the untreated, infected control. The major components detected by GC-MS in the supernatant revealed 10.86% palmitic acid (virulent), and 18.03% 1,3-dioxolane, 2,4,5-trimethyl- (avirulent), whereas the major component in the boiled supernatant was 2-hydroxy-gamma-butyrolactone in the virulent (21.17%) and avirulent (27.78%) strains. This is the first research that assessed the influence of boiled supernatant and dead cells of virulent and avirulent R.solanacearum strains in controlling bacterial wilt disease. Additional work is encouraged for further elucidation of such a topic.

Oleic Acid and Palmitic Acid from Bacteroides thetaiotaomicron and Lactobacillus johnsonii Exhibit Anti-Inflammatory and Antifungal Properties

A decrease in populations of Bacteroides thetaiotaomicron and Lactobacillus johnsonii is observed during the development of colitis and fungal overgrowth, while restoration of these populations reduces inflammatory parameters and fungal overgrowth in mice. This study investigated the effect of two fatty acids from B. thetaiotaomicron and L. johnsonii on macrophages and Caco-2 cells, as well as their impact on the inflammatory immune response and on Candida glabrata overgrowth in a murine model of dextran sulfate sodium (DSS)-induced colitis. Oleic acid (OA) and palmitic acid (PA) from L. johnsonii and B. thetaiotaomicron were detected during their interaction with epithelial cells from colon samples. OA alone or OA combined with PA (FAs) reduced the expression of proinflammatory mediators in intestinal epithelial Caco-2 cells challenged with DSS. OA alone or FAs increased FFAR1, FFAR2, AMPK, and IL-10 expression in macrophages. Additionally, OA alone or FAs decreased COX-2, TNFα, IL-6, and IL-12 expression in LPS-stimulated macrophages. In the DSS murine model, oral administration of FAs reduced inflammatory parameters, decreased Escherichia coli and Enterococcus faecalis populations, and eliminated C. glabrata from the gut. Overall, these findings provide evidence that OA combined with PA exhibits anti-inflammatory and antifungal properties.

A review of the ethnomedicinal uses, chemistry, and pharmacological properties of the genus Acanthus (Acanthaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

The Acanthus genus belongs to the Acanthaceae family, and its species are distributed in all continents, mainly in tropical and subtropical regions. Several traditional applications are referred to, but few scientific studies validate them. Despite this, studies in animal models corroborate some of its uses in folk medicine, such as anticancer, antidiabetic, anti-inflammatory, and antinociceptive, which encourages the research on plants of this genus.

AIM OF THE REVIEW

To our knowledge, this document is the first comprehensive review study that provides information on the geographic distribution, botanical characteristics, ethnomedicinal uses, phytochemicals, and pharmacological activities of some Acanthus species to understand the correlation between traditional uses, phytochemical, and pharmacological activities, providing perspectives for future studies.

RESULTS

In traditional medicine, Acanthus species are mainly used for diseases of respiratory, nervous and reproductive system, gastrointestinal and urinary tract, and skin illness. The most used species are A. montanus, A. ilicifolius, and A. ebracteatus. Chemical compounds (125) from different chemical classes were isolated and identified in seven species, mainly from A. ilicifolius, about 80, followed by A. ebracteatus and A. montanus, appearing with a slightly lower number with fewer phytochemical profile studies. Isolated phytoconstituents have been mainly alkaloids, phenylpropanoid glycosides, and phenylethanoids. In addition, aliphatic glycosides, flavonoids, lignan glycosides, megastigmane derivatives, triterpenoids, steroids, fatty acids, alcohols, hydroxybenzoic acids, simple phenols were also cited. Scientific studies from Acanthus species extracts and their phytoconstituents support their ethnomedical uses. Antimicrobial activity that is the most studied, followed by the antioxidant, anti-inflammatory, and anticancer properties, underlie many Acanthus species activities. A. dioscoridis, A. ebracteatus, A. hirsutus, A. ilicifolius, A. mollis, A. montanus, and A. polystachyus have studies on these activities, A. ilicifolius being the one with the most publications. Most studies were essentially performed in vitro. However, the anticancer, antidiabetic, anti-inflammatory and antinociceptive properties have been studied in vivo.

CONCLUSION

Acanthus species have remarkable phytoconstituents with different biological activities, such as antioxidant, antimicrobial, anti-inflammatory, antinociceptive, hepatoprotective, and leishmanicidal, supporting traditional uses of some species. However, many others remain unexplored. Future studies should focus on these species, especially pharmacological properties, toxicity, and action mechanisms. This review provides a comprehensive report on Acanthus genus plants, evidencing their therapeutic potential and prospects for discovering new safe and effective drugs from Acanthus species.

Characterization of a Novel Antimicrobial Peptide Isolated from Moringa oleifera Seed Protein Hydrolysates and Its Membrane Damaging Effects on Staphylococcus aureus

The present study sought to identify and characterize a novel antimicrobial peptide, named MOp2 from Moringa oleifera seed protein hydrolysates, and elucidate its potential antimicrobial effects on Staphylococcus aureus. MOp2, with the amino acid sequence of His-Val-Leu-Asp-Thr-Pro-Leu-Leu (HVLDTPLL), was characterized as a hydrophobic anionic AMP of the β-sheet structure. MOp2 exhibited negligible hemolytic activity at 2.0× MIC, suggesting its inhibitory effect on the growth of S. aureus (MIC: 2.204 mM). It maintained more than 90% of antimicrobial activity under 5% salt and about 78% of antimicrobial activity at a high temperature of 115 °C for 30 min. Protease, especially acid protease, reduced its antimicrobial activity to different extents. Moreover, MOp2 caused irreversible membrane damage to S. aureus cells by increasing the membrane permeability, resulting in the release of intracellular nucleotide pools. Additionally, molecular docking revealed that MOp2 could inhibit S. aureus growth by interacting with dihydrofolate reductase and DNA gyrase through hydrogen bonding and hydrophobic interactions. Overall, MOp2 could be a potential novel antimicrobial agent against S. aureus in food processing.

Streptococcus mutans and Candida albicans Biofilm Inhibitors Produced by Lactiplantibacillus plantarum CCFM8724

Lactiplantibacillus plantarum CCFM8724 inhibits the growth of Streptococcus mutans and Candida albicans in mixed-species biofilm formation. In this study, bioactive compound including cyclo (leu-pro), cyclo (phe-pro), and some organic acids, such as 3-phenyllactic acid, hydrocinnamic acid, and palmitic acid, were identified through GC-MS analysis. At 50 μg·mL^-1, cyclo (leu-pro) reduced biofilm mass (OD₆₀₀) from 3.00 to 2.00, and hydrocinnamic acid at 25 μg·mL^-1 reduced biofilm mass (OD₆₀₀) from 3.00 to 1.00. The expression of ALS3 and HWP1 was downregulated by cyclo (leu-pro). Furthermore, a mixture of cyclo (leu-pro), cyclo (phe-pro), 3-phenyllactic acid, hydrocinnamic acid, and palmitic acid, had anti-biofilm activity. Overall, the results provide promising baseline information for the potential use of this probiotic and its components in preventing biofilm formation.

Emerging Antifungal Targets and Strategies

Despite abundant research in the field of antifungal drug discovery, fungal infections remain a significant healthcare burden. There is an emerging need for the development of novel antifungals since those currently available are limited and do not completely provide safe and secure protection. Since the current knowledge regarding the physiology of fungal cells and the infection mechanisms is greater than ever, we have the opportunity to use this for the development of novel generations of antifungals. In this review, we selected and summarized recent studies describing agents employing different antifungal mechanisms. These mechanisms include interference with fungal resistance, including impact on the efflux pumps and heat shock protein 90. Additionally, interference with virulence factors, such as biofilms and hyphae; the impact on fungal enzymes, metabolism, mitochondria, and cell wall; and antifungal vaccines are explored. The agents investigated belong to different classes of natural or synthetic molecules with significant attention given also to plant extracts. The efficacy of these antifungals has been studied mainly in vitro with some in vivo, and clinical studies are needed. Nevertheless, there is a large quantity of products employing novel antifungal mechanisms that can be further explored for the development of new generation of antifungals.

Phytochemical Investigation of Pilea pumila (Clearweed), Laportea canadensis (Wood Nettle), and Boehmeria cylindrica (False Nettle): Three Members of the Urticaceae Family

Phytochemical analysis of 3 members of the Urticaceae family (eg Pilea pumila, Laportea canadensis, and Boehmeria cylindrica) was conducted using GC-MS. P pumila and L canadensis have several recorded historical medicinal uses by Native American tribes, whereas B cylindrica does not. This study was conducted to understand the historical uses in terms of chemical composition. Plant material, separated into aerial or root portions, was dried and extracted using either ethanol or heptane at room temperature. Sterols, fatty acids and esters, terpenes and terpenoids, saturated and monounsaturated hydrocarbons, small oxygen-functionalized organic molecules, and tocopherols were observed using these methods. Plant sterols composed 30.3% to 62.2% of the observed extracts, followed by fatty acids and esters ranging from 0% to 49% and terpenes and terpenoids ranging 4.56% to 33.9%. All 3 plants contained γ-sitosterol as the dominant plant sterol and palmitic, linoleic, and linolenic acids and esters. The 3 plants differed significantly in the observed terpene and terpenoid composition. Germacrene D-4-ol, known to have antifungal activity, was the major terpenoid identified in P pumila (7.42%-7.76%), phytol (4.13%), α-cadinene (3.96%), and cadina-1,4-diene (5.53%) were observed in L canadensis treatments, and squalene (2.20%-7.04%), phytol (4.17%), and cadina-1,4-diene (6.68%) were observed in B cylindrica treatments . Possible rationales for Native American medicinal uses were evaluated.

Green synthesis of selenium nanoparticles and evaluate their effect on the expression of ERG3, ERG11, and FKS1 antifungal resistance genes in Candida albicans and Candida glabrata

Drug resistance in Candida species has been considerably increased in the last decades. Given the opposition to antifungal agents, toxicity, and interactions of the antimicrobial drugs, identifying new antifungal agents seems essential. This study assessed the antifungal effects of nanoparticles (NPs) on the standard strains of Candida albicans and Candida glabrata and determined the expression genes, including ERG3, ERG11, and FKS1. Selenium nanoparticles (Se-NPs) were biosynthesized with a standard strain of C. albicans and approved by several methods including, UV-Vis spectrophotometer, XRD technique, FTIR analysis, FESEM microscopy, and EDX diagram. The antifungal susceptibility testing performed the minimum inhibitory concentrations (MICs) using the CLSI M27-A3 and M27-S4 broth microdilution method. The expression of the desired genes was examined by the real-time PCR assay between untreated and treated by antifungal drugs and Se-NPs. The MICs of itraconazole, amphotericin B, and anidulafungin against C. albicans and C. glabrata were 64, 16, and 4 µg/ml. In comparison, reduced the MIC values ​​for samples treated with Se-NPs to 1 and 0.5 µg/ml. The results obtained from real-time PCR and analysis of the ∆∆C_q values showed that the expression of ERG3, ERG11, and FKS1 genes was significantly down-regulated in Se-NPs concentrations (P<0.05). This study's evidence implies biosafety Se-NPs have favorable effects on the reducing expression of ERG3, ERG11, and FKS1 antifungal resistance genes in C. albicans and C. glabrata.

Fatty acids compositional variations between the edible and non-edible fruit part of seven pomegranate varieties

The biological importance of fatty acids in different metabolic routes and/or specific activities with medical, cosmetic, pharmaceutical interest makes it increasingly necessary to know in detail the lipid composition of foods. The objective of this work was to identify and characterize the fatty acids profile of seven pomegranate varieties with commercial interest, differentiating between its edible (seeds) and non-edible (peel plus carpellary membranes) parts, aiming to have a holistic and characteristic vision. The results confirmed the compositional fatty acids variations of the pomegranate, both between different varieties and the parts of the fruit. 29-101 variety presents a fatty acid profile with a higher potential for antifungal, antibacterial and antiviral properties. The content of punicic acid in the Kingdom variety makes it the most pomegranate varieties interesting for its nutraceutical, pharmaceutical, food and medical applications. The specific fatty acid content could define the best pomegranate variety depending on its potential use/application.

Microalgae and Cyanobacteria Strains as Producers of Lipids with Antibacterial and Antibiofilm Activity

Lipids are one of the primary metabolites of microalgae and cyanobacteria, which enrich their utility in the pharmaceutical, feed, cosmetic, and chemistry sectors. This work describes the isolation, structural elucidation, and the antibiotic and antibiofilm activities of diverse lipids produced by different microalgae and cyanobacteria strains from two European collections (ACOI and LEGE-CC). Three microalgae strains and one cyanobacteria strain were selected for their antibacterial and/or antibiofilm activity after the screening of about 600 strains carried out under the NoMorFilm European project. The total organic extracts were firstly fractionated using solid phase extraction methods, and the minimum inhibitory concentration and minimal biofilm inhibitory concentration against an array of human pathogens were determined. The isolation was carried out by bioassay-guided HPLC-DAD purification, and the structure of the isolated molecules responsible for the observed activities was determined by HPLC-HRESIMS and NMR methods. Sulfoquinovosyldiacylglycerol, monogalactosylmonoacylglycerol, sulfoquinovosylmonoacylglycerol, α-linolenic acid, hexadeca-4,7,10,13-tetraenoic acid (HDTA), palmitoleic acid, and lysophosphatidylcholine were found among the different active sub-fractions selected. In conclusion, cyanobacteria and microalgae produce a great variety of lipids with antibiotic and antibiofilm activity against the most important pathogens causing severe infections in humans. The use of these lipids in clinical treatments alone or in combination with antibiotics may provide an alternative to the current treatments.

Mode of action and efficacy of quinolinic acid for the control of Ceratocystis fimbriata on sweet potato

BACKGROUND

Ceratocystis fimbriata is a hazardous fungal pathogen able to cause black rot disease on sweet potato. The management of C. fimbriata strongly relies on the use of toxic fungicides, and there is a lack of efficient alternative strategies.

RESULTS

The antifungal properties of quinolinic acid (QA) were studied for the first time, indicating that QA shows selective antifungal activity against C. fimbriata. QA inhibited completely the mycelial growth of C. fimbriata at less than 0.8 mg mL^-1 concentration (pH 4), and was able to produce alterations in the fungal cell wall, and to impede spore agglutination and mycelium formation. QA significantly reduced the concentration of ergosterol, and was able to associate to iron (II), suggesting that QA may be a lanosterol 14-α demethylase inhibitor. In preventive applications, QA reduced the disease incidence of C. fimbriata on sweet potato by 75%, achieving higher control efficacy in comparison with commercial fungicides prochloraz and carbendazim.

CONCLUSIONS

The first selective antifungal agent against C. fimbriata was discovered in this work, and showed suitable antifungal properties for the management of black rot disease. © 2021 Society of Chemical Industry.

Antibiofilm and antimicrobial efficacy evaluation of polypyrrole nanotubes embedded in aminated gum acacia based nanocomposite

The sustainable development of natural polysaccharide-based hybrid composites is highly important for the effective replacement of metal nanoparticles in diverse applications. Here, polypyrrole nanotubes (PPyNTs) were embedded on the surface of aminated gum acacia (AGA) to produce ecofriendly nanocomposites for biomedical applications. The morphology of a PPyNT-enhanced AGA (PPyNT@AGA) hybrid nanocomposite was studied by scanning electron microscopy and transmission electron microscopy and their affirmed interactions were characterised by X-ray diffraction, Raman, Fourier transform-infrared and UV-visible spectroscopy. Interestingly, the prepared PPyNT@AGA nanocomposite exhibited 90% biofilm inhibition against gram-negative Pseudomonas aeruginosa, gram-positive Streptococcus pneumoniae and fungal strain Candida albicans with promising antimicrobial performance. This study establishes the good inhibition of a PPyNT@AGA hybrid composite against various microorganisms. The stability of the nanocomposite coupled with antimicrobial activity enables an effective strategy for diagnosing and controlling pathogens.

Current and promising pharmacotherapeutic options for candidiasis

Introduction: Candida spp. are commensal yeasts capable of causing infections such as superficial, oral, vaginal, or systemic infections. Despite medical advances, the antifungal pharmacopeia remains limited and the development of alternative strategies is needed.Areas covered: We discuss available treatments for Candida spp. infections, highlighting advantages and limitations related to pharmacokinetics, cytotoxicity, and antimicrobial resistance. Moreover, we present new perspectives to improve the activity of the available antifungals, discussing their immunomodulatory potential and advances on drug delivery carriers. New therapeutic approaches are presented including recent synthesized antifungal compounds (Enchochleated-Amphotericin B, tetrazoles, rezafungin, enfumafungin, manogepix and arylamidine); drug repurposing using a diversity of antibacterial, antiviral and non-antimicrobial drugs; combination therapies with different compounds or photodynamic therapy; and innovations based on nano-particulate delivery systems.Expert opinion: With the lack of novel drugs, the available assets must be leveraged to their best advantage through modifications that enhance delivery, efficacy, and solubility. However, these efforts are met with continuous challenges presented by microbes in their infinite plight to resist and survive therapeutic drugs. The pharmacotherapeutic options in development need to focus on new antimicrobial targets. The success of each antimicrobial agent brings strategic insights to the next phased approach in treatingCandida spp. infections.

Exploring the druggable proteome of Candida species through comprehensive computational analysis

Candida albicans and non-albicans Candida spp. are major cause of systemic mycoses. Antifungal drugs such as azoles and polyenes are not efficient to successfully eradicate Candida infection owing to their fungistatic nature or low bioavailability. Here, we have adopted a comprehensive computational workflow for identification, prioritization and validation of targets from proteomes of Candida albicans and Candida tropicalis. The protocol involves identification of essential drug-target candidates using subtractive genomics, protein-protein interaction network properties and systems biology based methods. The essentiality of the novel metabolic and non-metabolic targets was established by performing in silico gene knockouts, under aerobic as well as anaerobic conditions, and in vitro drug inhibition assays respectively. Deletion of twelve genes that are involved in amino acid, secondary metabolite, and carbon metabolism showed zero growth in metabolic model under simulated conditions. The algorithm, used in this study, can be downloaded from http://pbit.bicnirrh.res.in/offline.php and executed locally.

Anti-inflammatory potential of myristic acid and palmitic acid synergism against systemic candidiasis in Danio rerio (Zebrafish)

Nosocomial Candida colonization causes Systemic candidiasis in human with invasive infections in immunocompromised patients. Of all Candida spp., C. albicans is dominant in morbidity of all systemic candidiasis but C. tropicalis is phenomenal in mortality, virulence aspects and resistance development against antifungal drugs. The present study investigated the synergistic anti-virulent activity of myristic acid (MA) and palmitic acid (PA) against insidious dimorphic Candida spp. (C. albicans and C. tropicalis). In vitro and qPCR results revealed the mechanisms of MA-PA combination effectively inhibiting various virulence aspects such as biofilm, hyphal formation, secreted aspartyl proteases, lipases, ergosterol biosynthesis and drug effluxes. Further, in Danio rerio (Zebrafish), the MA-PA treatment increased the survival of animals and also the treated groups showed decreased level of fungal burden compared to the infected controls, after 3^rd day of post infection. Histopathology of vital organs and SEM analysis of skin revealed a drastic recovery and reduced the inflammation of both Candida spp. infections in MA-PA treated animals. In addition, MA-PA treatment reduced the haemolysin and increased the susceptibility of Candida spp. in human blood model. Hence, this study suggested the therapeutic utilization of MA-PA as synergistic combination for their anti-inflammatory potency against systemic candidiasis and candidemia.

Carvacrol Targets SarA and CrtM of Methicillin-Resistant Staphylococcus aureus to Mitigate Biofilm Formation and Staphyloxanthin Synthesis: An In Vitro and In Vivo Approach

Carvacrol is an essential oil traditionally used in culinary processes as spice due to its aromatic nature and also known for various biological activities. In the present study, the antivirulence efficacy of carvacrol against methicillin-resistant Staphylococcus aureus (MRSA) is explored. MRSA is an opportunistic pathogen capable of causing various superficial and systemic infections in humans. Biofilm formation and virulence factors of MRSA are responsible for its pathogenesis and resistance. Hence, the aim of this study was to explore the antibiofilm and antivirulence efficacy of carvacrol against MRSA. Carvacrol at 75 μg/mL inhibited MRSA biofilm by 93%, and it also decreased the biofilm formation on polystyrene and glass surfaces. Further, microscopic analyses revealed the reduction in microcolony formation and collapsed structure of biofilm upon carvacrol treatment. The growth curve analysis and the Alamar blue assay showed the nonfatal effect of carvacrol on MRSA. Further, carvacrol significantly reduced the production of MRSA biofilm-associated slime and extracellular polysaccharide. In addition, carvacrol strongly inhibited the antioxidant pigment staphyloxanthin and its intermediates' synthesis in MRSA. Inhibition of biofilm and staphyloxanthin by carvacrol enhanced the susceptibility of MRSA to oxidants and healthy human blood. Quantitative polymerase chain reaction (qPCR) analysis unveiled the downregulation of sarA-mediated biofilm gene expression and staphyloxanthin-associated crtM gene expression. The sarA-dependent antibiofilm potential of carvacrol was validated using S. aureus Newman wild-type and isogenic ΔsarA strains. In silico molecular docking analysis showed the high binding efficacy of carvacrol with staphylococcal accessory regulator A (SarA) and 4,4'-diapophytoene synthase (CrtM) when compared to positive controls. Furthermore, the in vivo efficacy of carvacrol against MRSA infection was demonstrated using the model organism Galleria mellonella. The results revealed the nontoxic nature of carvacrol to the larvae and the rescuing potential of carvacrol against MRSA infection. Finally, the current study reveals the potential of carvacrol in inhibiting the biofilm formation and staphyloxanthin synthesis of MRSA by targeting the global regulator SarA and a novel antivirulence target CrtM.

In Vitro and In Silico Analysis of Ascorbic Acid Towards Lanosterol 14-α-Demethylase Enzyme of Fluconazole-Resistant Candida albicans

Antibiotic resistance is one of the major concerns and the biggest threats to the world population. The incidents of antibiotic resistance in Candida spp. were frequently recorded. In the present investigation, antifungal potential of ascorbic acid (AA) was evaluated. According to the in vitro analysis, the zone of inhibition of AA (24.75 ± 0.35 mm) against C. albicans was greater as compared to other vitamins tested. AA significantly modulate the growth of C. albicans at 25 mg/ml. The highest percentage (94.67%) of cell viability was observed in untreated cells, and low cell viability (29.36%) was observed in cells treated with 50 mg/ml of AA (2 × MIC). Further, AO/EB (acridine orange/ethidium bromide), propidium iodide staining, and real-time qPCR confirmed the loss of membrane integrity due to membrane lesions that caused cell death. Lanosterol 14-α-demethylase (L-14α-DM) is the product of ERG11 and acted as superior drug target of C. albicans. Molecular docking analysis confirmed that active interaction of ascorbic acid with L-14α-DM. Based on the present investigation, the efficiency of AA was effectively proved through the in vitro and in silico analysis. This finding has evidenced the effectiveness of AA as a potential candidate against C. albicans.