Bioactivity of Amphidinol-Containing Extracts of Amphidinium carterae Grown Under Varying Cultivation Conditions.

Microalgae are of great interest due to their ability to produce valuable compounds, such as pigments, omega-3 fatty acids, antioxidants, and antimicrobials. The dinoflagellate genus Amphidinium is particularly notable for its amphidinol-like compounds, which exhibit antibacterial and antifungal properties. This study utilized a two-stage cultivation method to grow Amphidinium carterae CCAP 1102/8 under varying conditions, such as blue LED light, increased salinity, and the addition of sodium carbonate or hydrogen peroxide. After cultivation, the biomass was extracted and fractionated using solid-phase extraction, yielding six fractions per treatment. These fractions were analyzed using Liquid Chromatography-High-Resolution Mass Spectrometry (LC-HRMS/MS) to identify their chemical components. Key amphidinol compounds (AM-B, AM-C, AM-22, and AM-A) were identified, with AM-B being the most abundant in Fraction 4, followed by AM-C. Fraction 5 also contained a significant amount of AM-C along with an unknown compound. Fraction 4 returned the highest antimicrobial activity against the pathogens Staphylococcus aureus, Enterococcus faecalis, and Candida albicans, with Minimal Biocidal Concentrations (MBCs) ranging from 1 to 512 µg/mL. Results indicate that the modulation of both amphidinol profile and fraction bioactivity can be induced by adjusting the cultivation parameters used to grow two-stage batch cultures of A. carterae.

Unraveling the effective inhibition of α-terpinol and terpene-4-ol against Aspergillus carbonarius: Antifungal mechanism, ochratoxin A biosynthesis inhibition and degradation perspectives.

Aspergillus carbonarius, a common food-contaminating fungus, produces ochratoxin A (OTA) and poses a risk to human health. This study aimed to assess the inhibitory activity of tea tree essential oil and its main components, Terpene-4-ol (T4), α-terpineol (αS), and 3-carene (3C) against A. carbonarius. The study showed αS and T4 were the main antifungal components of tea tree essential oil, which primarily inhibit A. carbonarius growth through cell membrane disruption, reducing antioxidant enzyme activities (catalase, peroxidase, superoxide dismutase) and interrupting the tricarboxylic acid cycle. Furthermore, αS and T4 interacted with enzymes related to OTA biosynthesis. Molecular docking and molecular dynamics show that they bound mainly to P450 with a minimum binding energy of -7.232 kcal/mol, we infered that blocking the synthesis of OTA precursor OTß. Our hypothesis was preliminarily verified by the detection of key substances in the OTA synthesis pathway. The results of UHPLC-QTOF-MS2 analysis demonstrated that T4 achieved a degradation rate of 43 % for OTA, while αS reached 29.6 %, resulting in final breakdown products such as OTα and phenylalanine. These results indicated that α-terpinol and Terpene-4-ol have the potential to be used as naturally safe and efficient preservatives or active packaging to prevent OTA contamination.

Exploring Brominated Aromatic Butenolides from Aspergillus terreus EGF7-0-1 with Their Antifungal Activities.

Fungal diseases could severely harm agricultural productions. To develop new antifungal agents, based on the Global Natural Products Social Molecular Networking, typical bromine isotope peak ratios, and ultraviolet absorptions, cultivation of the soft coral-derived endophytic fungi Aspergillus terreus EGF7-0-1 with NaBr led to the targeted isolation of 14 new brominated aromatic butenolides (1-14) and six known analogues (15-20). Their structures were elucidated by extensive spectroscopic analysis and quantum chemical calculations. Compounds 1-14 exhibited wildly antifungal activities (against Colletotrichum gloeosporioides, Pestalotiopsis microspora, Fusarium oxysporum f. sp. cubense, Botrytis cinerea, and Diaporthe phoenicicola). The bioassay results showed that compounds 1-14 exhibited excellent antifungal activities against C. gloeosporioides, with concentration for 50% of maximal effect (EC50) values from 2.72 to 130.41 nM. The mechanistic study suggests that compound 1 may disrupt nutrient signaling pathways by reducing the levels of metabolites, such as carbohydrates, lipids, and amino acids, leading to an increase in low-density granules and a decrease in high-density granules in the cytoplasm, accompanied by numerous vacuoles, thereby inhibiting the growth of C. gloeosporioides. Monobrominated γ-butenolide 1 may be expected to exploit a novel agriculturally antifungal leading drug. Meanwhile, compound M1 has conformed antifugual activities against C. gloeosporioides by papayas in vivo.

Unveiling the potential of novel Metschnikowia yeast biosurfactants: triggering oxidative stress for promising antifungal and anticancer activity.

BACKGROUND: Sophorolipids are glycolipid biosurfactants with potential antibacterial, antifungal, and anticancer applications, rendering them promising for research. Therefore, this study hypothesizes that sophorolipids may have a notable impact on disrupting membrane integrity and triggering the production of reactive oxygen species, ultimately resulting in the eradication of pathogenic microbes. RESULTS: The current study resulted in the isolation of two Metschnikowia novel yeast strains. Sophorolipids production from these strains reached maximum yields of 23.24 g/l and 21.75 g/l, respectively, at the bioreactors level. Biosurfactants sophorolipids were characterized using FTIR and LC-MS techniques and found to be a mixture of acidic and lactonic forms with molecular weights of m/z 678 and 700. Our research elucidated sophorolipids' mechanism in disrupting bacterial and fungal membranes through ROS generation, confirmed by transmission electron microscopy and FACS analysis. The results showed that these compounds disrupted the membrane integrity and induced ROS production, leading to cell death in Klebsiella pneumoniae and Fusarium solani. In addition, the anticancer properties of sophorolipids were investigated on the A549 lung cancer cell line and found that sophorolipid-11D (SL-11D) and sophorolipid-11X (SL-11X) disrupted the actin cytoskeleton, as evidenced by immunofluorescence microscopy. The A549 cells were stained with Acridine orange/Ethidium bromide, which showed that they underwent necrosis. This was confirmed by flow cytometric analysis using Annexin/PI staining. The SL-11D and SL-11X molecules exhibited low levels of haemolytic activity and in-vitro cytotoxicity in HEK293, Caco-2, and L929 cell lines. CONCLUSION: In this work, novel yeast species CIG-11DT and CIG-11XT, isolated from the bee's gut, produce significant yields of sophorolipids without needing secondary oil sources, indicating a more economical production method. Our research shows that sophorolipids disrupt bacterial and fungal membranes via ROS production. They suggest they may act as chemo-preventive agents by inducing apoptosis in lung cancer cells, offering the potential for enhancing anticancer therapies.

Phyto-assisted synthesis of zinc oxide nanoparticles using Bauhinia variegata buds extract and evaluation of their multi-faceted biological potentials.

Zinc oxide nanoparticles have wide range biological, biomedical and environmental applications. However, traditional nanofabrication of ZnONPs uses various toxic chemicals and organic solvents which limit their bio-applications. To overcome this hurdle, Bauhinia variegata derived buds extract was utilized to fabricate ZnONPs. The greenly generated ZnONPs were successfully prepared and extensively characterized using different analytical tools and the average crystalline size was calculated as 25.47 nm. Further, bioengineered ZnONPs were explored for multiple biological activities that revealed excellent therapeutic potentials. The antibacterial potential was determined using different bacterial strains. Pseudomonas aeruginosa (MIC: 137.5 µg/mL) was reported to be the most resistant variant while Bacillus subtilis (MIC: 34.38 µg/mL) was observed to be most susceptible bacterial strain. DPPH radical scavenging potential was measured to determine the antioxidant capacity of ZnONPs and the highest scavenging potential was observed as 82% at highest of 300 µg/mL. The fungicidal effect of green ZnONPs in comparison with Amphotericin B was assessed against five selected pathogenic fungal strains. The results revealed, Fusarium solani (MIC: 46.875 µg/mL) was least resistant and Aspergillus flavus (MIC: 187.5 µg/mL) was most resistant in fungicidal examination. Cytotoxicity potential of B.V@ZnONPs was analyzed against newly hatched nauplii of brine shrimps. The results for greenly produced ZnONPs was recorded as 39.78 µg/mL while 3.006 µg/mL was reported for positive control vincristine sulphate. The results confirmed the category of general cytotoxic for greenly synthesized nano sized B.V@ZnONPs.

Design, Synthesis, and Antimicrobial Activity of Amide Derivatives Containing Cyclopropane.

As an important small organic molecule, cyclopropane is widely used in drug design. In this paper, fifty-three amide derivatives containing cyclopropane were designed and synthesized by introducing amide groups and aryl groups into cyclopropane through the active splicing method, and their antibacterial and antifungal activities were evaluated in vitro. Among them, thirty-five compounds were new compounds, and eighteen compounds were known compounds (F14, F15, F18, F20-F26, F36, and F38-F44). Bioassay results disclosed that four, three, and nine of the compounds showed moderate activity against Staphylococcus aureus, Escherichia coli, and Candida albicans, respectively. Three compounds were sensitive to Candida albicans, with excellent antifungal activity (MIC80 = 16 µg/mL). The molecular docking results show that compounds F8, F24, and F42 have good affinity with the potential antifungal drug target CYP51 protein.

Cryo-EM structures of Candida albicans Cdr1 reveal azole-substrate recognition and inhibitor blocking mechanisms.

In Candida albicans, Cdr1 pumps azole drugs out of the cells to reduce intracellular accumulation at detrimental concentrations, leading to azole-drug resistance. Milbemycin oxime, a veterinary anti-parasitic drug, strongly and specifically inhibits Cdr1. However, how Cdr1 recognizes and exports azole drugs, and how milbemycin oxime inhibits Cdr1 remain unclear. Here, we report three cryo-EM structures of Cdr1 in distinct states: the apo state (Cdr1Apo), fluconazole-bound state (Cdr1Flu), and milbemycin oxime-inhibited state (Cdr1Mil). Both the fluconazole substrate and the milbemycin oxime inhibitor are primarily recognized within the central cavity of Cdr1 through hydrophobic interactions. The fluconazole is suggested to be exported from the binding site into the environment through a lateral pathway driven by TM2, TM5, TM8 and TM11. Our findings uncover the inhibitory mechanism of milbemycin oxime, which inhibits Cdr1 through competition, hindering export, and obstructing substrate entry. These discoveries advance our understanding of Cdr1-mediated azole resistance in C. albicans and provide the foundation for the development of innovative antifungal drugs targeting Cdr1 to combat azole-drug resistance.

Experimental and computational insights of Albizia amara phytoconstituents targeting anthranilate phosphoribosyltransferase from Malassezia globosa.

The fungus Malassezia globosa is often responsible for superficial mycoses posing significant treatment challenges because of the unfavourable side effects of available antifungal drugs. To reduce potential hazards to the host and overcome these hurdles, new therapeutic medicines must be developed that selectively target enzymes unique to the pathogen. This study focuses on the enzyme anthranilate phosphoribosyltransferase (AnPRT), which is vital to M. globosa's tryptophan production pathway. To learn more about the function of the AnPRT enzyme, we modeled, validated, and simulated its structure. Moreover, many bioactive components were found in different extracts from the plant Albizia amara after phytochemical screening. Interestingly, at doses ranging from 500 to 2000 µg/ml, the chloroform extract showed significant antifungal activity, with inhibition zones measured between 11.0 ± 0.0 and 25.6 ± 0.6 mm. According to molecular docking analyses, the compounds from the active extract, particularly 2-tert-Butyl-4-isopropyl-5-methylphenol, interacted with the AnPRT enzyme's critical residues, ARG 205 and PHE 214, with an effective binding energy of -4.9 kcal/mol. The extract's revealed component satisfies the requirements for drug-likeness and shows promise as a strong antifungal agent against infections caused by M. globosa. These findings imply that using plant-derived chemicals to target the AnPRT enzyme is a viable path for the creation of innovative antifungal treatments.

Optimizing antimicrobial synergy: Green synthesis of silver nanoparticles from Calotropis gigantea leaves enhanced by patchouli oil.

Silver nanoparticles (AgNPs) synthesized from plant extracts have gained attention for their potential applications in biomedicine. Calotropis gigantea has been utilized to synthesize AgNPs, called AgNPs-LCg, and exhibit antibacterial activities against both Gram-positive and Gram-negative bacteria as well as antifungal. However, further enhancement of their antimicrobial properties is needed. The aim of this study was to synthesize AgNPs-LCg and to enhance their antimicrobial and antifungal activities through a hybrid green synthesis reaction using patchouli oil (PO), as well as to characterize the synthesized AgNPs-LCg. Optimization was conducted using the response surface method (RSM) with a central composite design (CCD). AgNPs-LCg were synthesized under optimal conditions and hybridized with different forms of PO-crude, distillation wastewater (hydrolate), and heavy and light fractions-resulting in PO-AgNPs-LCg, PH-AgNPs-LCg, LP-AgNPs-LCg, and HP-AgNPs-LCg, respectively. The samples were then tested for their antibacterial (both Gram-positive and Gram-negative bacteria) and antifungal activities. Our data indicated that all samples, including those with distillation wastewater, had enhanced antimicrobial activity. HP-AgNPs-LCg, however, had the highest efficacy; therefore, only HP-AgNPs-LCg proceeded to the characterization stage for comparison with AgNPs-LCg. UV-Vis spectrophotometry indicated surface plasmon resonance (SPR) peaks at 400 nm for AgNPs-LCg and 360 nm for HP-AgNPs-LCg. The Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the presence of O-H, N-H, and C-H groups in C. gigantea extract and AgNP samples. The smallest AgNPs-LCg were 56 nm, indicating successful RSM optimization. Scanning electron microscopy (SEM) analysis revealed spherical AgNPs-LCg and primarily cubic HP-AgNPs-LCg, with energy-dispersive X-ray spectroscopy (EDX) confirming silver's predominance. This study demonstrated that PO in any form significantly enhances the antimicrobial properties of AgNPs-LCg. The findings pave the way for the exploration of enhanced and environmentally sustainable antimicrobial agents, capitalizing on the natural resources found in Aceh Province, Indonesia.

Prolonged retention of luliconazole nanofibers for topical mycotic condition: development, in vitro characterization and antifungal activity against Candida albicans.

An antifungal agent, luliconazole, is commercially available in cream or gel form. The major limitation of these conventional formulations is less residence time at the infection site. The primary objective of this work was to develop luliconazole-loaded polyvinyl alcohol (Luz-PVA) nanofibers for mycotic skin conditions with a longer retention. Luz-PVA nanofibers were prepared by plate electrospinning and optimized for polymer concentration and process parameters. The optimized batch (Trial 5) was prepared by 10% PVA, processed at 22.4 kV applied voltage, and 14 cm plate and spinneret distance to yield thick, uniform, and peelable nanofibers film. There was no interaction observed between Luz and PVA in the FTIR study. DSC and XRD analysis showed that luliconazole was loaded into fabricated nanofibers with a reduced crystallinity. FESEM studies confirmed the smooth, defect-free mats of nanofibers. Luz-PVA nanofibers possessed a tensile strength of 21.8 N and a maximum elongation of 10.8%, representing the excellent elasticity of the scaffolds. For Luz-PVA nanofibers, the sustained and complete drug release was observed in 48 h. In antifungal activity using Candida albicans, the Luz-PVA nanofibers showed a greater zone of inhibition (30.55 ± 0.38 mm and 29.27 ± 0.31 mm) than marketed cream (28.06 ± 0.18 mm and 28.47 ± 0.24 mm) and pure drug (27.57 ± 0.17 mm and 27.50 ± 0.47 mm) at 1% concentration in Sabouraud dextrose agar and yeast malt agar, respectively. Therefore, Luz-PVA nanofibers exhibited good mechanical properties, longer retention time, and better antifungal activity than marketed products and, therefore, can be further examined preclinically as a potential treatment option for topical mycotic infection.

The antimicrobial effects of silver nanoparticles obtained through the royal jelly on the yeasts Candida guilliermondii NP-4.

The effect of silver nanoparticles (Ag NPs) obtained in the presence of royal jelly (RJ) on the growth of yeast Candida guilliermondii NP-4, on the total and H+-ATPase activity, as well as lipid peroxidation process and antioxidant enzymes (superoxide dismutase (SOD), catalase) activity was studied. It has been shown that RJ-mediated Ag NPs have a fungicide and fungistatic effects at the concentrations of 5.4 µg mL-1 and 27 µg mL-1, respectively. Under the influence of RJ-mediated Ag NPs, a decrease in total and H+-ATPase activity in yeast homogenates by ~ 90% and ~ 80% was observed, respectively. In yeast mitochondria total and H+-ATPase activity depression was detected by ~ 80% and ~ 90%, respectively. The amount of malondialdehyde in the Ag NPs exposed yeast homogenate increased ~ 60%, the catalase activity increased ~ 70%, and the SOD activity-~ 30%. The obtained data indicate that the use of RJ-mediated Ag NPs have a diverse range of influence on yeast cells. This approach may be important in the field of biomedical research aimed at evaluating the development of oxidative stress in cells. It may also contribute to a more comprehensive understanding of antimicrobial properties of RJ-mediated Ag NPs and help control the proliferation of pathogenic fungi.

Antifungal, molecular docking and cytotoxic effect of the essential oil of Cymbopogon citratus (DC) Stapf. and Cymbopogon nardus (L.) Rendle against Candida albicans.

Brazil is renowned for its extensive plant biodiversity, with emphasis on Cymbopogon, C. citratus and C. nardus, with broad antimicrobial potential. Candidemias caused by Candida albicans are highly prevalent in immunosuppressed individuals and are associated with infections by biofilms on medical devices. The aim of this study was to evaluate the antimicrobial potential of essential oils C. citratus and C. nardus against C. albicans in planktonic and biofilm forms. Essential oils were obtained by hydrodistillation and chemical composition evaluated by GC-FID and GC-MS. The minimum inhibitory concentration was determined by the broth microdilution method and the synergy effect of essential oils and amphotericin B were evaluated by the checkerboard test. Biofilm activity was determined by the XTT assay. Cytotoxicity assays performed with VERO cells and molecular docking were performed to predict the effect of oil interaction on the SAP-5 enzyme site. The results showed activity of essential oils against planktonic cells and biofilm of C. albicans. Furthermore, the oils had a synergistic effect, and low cytotoxicity. Molecular docking showed interaction between Cadinene, Caryophyllen oxide, Germacrene D with SAP-5. The results indicate that Cymbopogon spp. studied are anti-Candida, with potential for further application in therapy against infections caused by C. albicans.

Tailored Sticky Solutions: 3D-Printed Miconazole Buccal Films for Pediatric Oral Candidiasis.

In this research, 3D-printed antifungal buccal films (BFs) were manufactured as a potential alternative to commercially available antifungal oral gels addressing key considerations such as ease of manufacturing, convenience of administration, enhanced drug efficacy and suitability of paediatric patients. The fabrication process involved the use of a semi-solid extrusion method to create BFs from zein-Poly-Vinyl-Pyrrolidone (zein-PVP) polymer blend, which served as a carrier for drug (miconazole) and taste enhancers. After manufacturing, it was determined that the disintegration time for all films was less than 10 min. However, these films are designed to adhere to buccal tissue, ensuring sustained drug release. Approximately 80% of the miconazole was released gradually over 2 h from the zein/PVP matrix of the 3D printed films. Moreover, a detailed physicochemical characterization including spectroscopic and thermal methods was conducted to assess solid state and thermal stability of film constituents. Mucoadhesive properties and mechanical evaluation were also studied, while permeability studies revealed the extent to which film-loaded miconazole permeates through buccal tissue compared to commercially available oral gel formulation. Histological evaluation of the treated tissues was followed. Furthermore, in vitro antifungal activity was assessed for the developed films and the commercial oral gel. Finally, films underwent a two-month drug stability test to ascertain the suitability of the BFs for clinical application. The results demonstrate that 3D-printed films are a promising alternative for local administration of miconazole in the oral cavity.

Antifungal and Antibacterial Activities of Crude Extracts of Four Phellinus Species and Coltricia fragilissima (Agaricomycetes) from Cameroon and Democratic Republic of Congo.

Antifungal and antibacterial activities of crude extracts of Phellinus extensus, Ph. gilvus, Ph. pachyphloeus, Ph. senex and Coltricia fragilissima were investigated on eleven species of bacteria and three fungal human pathogens. The minimum inhibitory concentration (MIC) was determined by the microdilution method. The results of this study reveal that for the eleven strains of bacteria tested, including Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, S. epidermidis, Enterobacter cloacae, Klebsiella aerogenes, Mycobacterium smegmatis, Proteus vulgaris, Proteus mirabilis and Escherichia choli, the MIC of the crude extract of the four species of Phellinus as well as that of C. fragilissima ranged from 3.13 to 12.50 mg/mL. For the three strains of fungi tested including Candida albicans, Aspergillus ochraceus and A. fumigetus, the MIC of the crude extracts of the same four species of Phellinus as well as that of C. fragilissima ranged from 0.39 to 3.13 mg/mL. These data reveal that the antimicrobial activity of crude extracts of Phellinus and Coltricia species is stronger on pathogenic fungi than on bacteria. C. fragilissima being of the same family as Phellinus and having recorded the values of MIC eminently close to those of the latter may potentially be used for medicinal purposes like the investigated Phellinus species. Being highly represented in the sub-Saharan regions and owing to the above-mentioned results, these species could now be considered as part of the non-exhaustive list of medicinal mushrooms in these regions and may constitute a new source of natural molecules that may be more active than synthetic products against certain fungal and bacterial borne diseases.

Green Synthesis and Antifungal Activities of Novel N-Aryl Carbamate Derivatives.

Carbamate is a key structural motif in the development of fungicidal compounds, which is still promising and robust in the discovery of green pesticides. Herein, we report the synthesis and evaluation of the fungicidal activity of 35 carbamate derivatives, among which 19 compounds were synthesized in our previous report. These derivatives were synthesized from aromatic amides in a single step, which was a green oxidation process for Hofmann rearrangement using oxone, KCl and NaOH. Their chemical structures were characterized by 1H NMR, 13C NMR and high-resolution mass spectrometry. Their antifungal activity was tested against seven plant fungal pathogens. Many of the compounds exhibited good antifungal activity in vitro (inhibitory rate > 60% at 50 µg/mL). Compound 1ag exhibited excellent broad-spectrum antifungal activities with inhibition rates close to or higher than 70% at 50 µg/mL. Notably, compound 1af demonstrated the most potent inhibition against F. graminearum, with an EC50 value of 12.50 µg/mL, while compound 1z was the most promising candidate fungicide against F. oxysporum (EC50 = 16.65 µg/mL). The structure-activity relationships are also discussed in this paper. These results suggest that the N-aryl carbamate derivatives secured by our green protocol warrant further investigation as potential lead compounds for novel antifungal agents.

Antifungal Mechanism of Ruta graveolens Essential Oil: A Colombian Traditional Alternative against Anthracnose Caused by Colletotrichum gloeosporioides.

Here, we report for the first time on the mechanisms of action of the essential oil of Ruta graveolens (REO) against the plant pathogen Colletotrichum gloeosporioides. In particular, the presence of REO drastically affected the morphology of hyphae by inducing changes in the cytoplasmic membrane, such as depolarization and changes in the fatty acid profile where straight-chain fatty acids (SCFAs) increased by up to 92.1%. In addition, REO induced changes in fungal metabolism and triggered apoptosis-like responses to cell death, such as DNA fragmentation and the accumulation of reactive oxygen species (ROS). The production of essential enzymes involved in fungal metabolism, such as acid phosphatase, ß-galactosidase, ß-glucosidase, and N-acetyl-ß-glucosaminidase, was significantly reduced in the presence of REO. In addition, C. gloeosporioides activated naphthol-As-BI phosphohydrolase as a mechanism of response to REO stress. The data obtained here have shown that the essential oil of Ruta graveolens has a strong antifungal effect on C. gloeosporioides. Therefore, it has the potential to be used as a surface disinfectant and as a viable replacement for fungicides commonly used to treat anthracnose in the postharvest testing phase.

Synthesis and Biological Activities of C1-Substituted Acylhydrazone ß-Carboline Analogues as Antifungal Candidates.

In our ongoing work to create potential antifungal agents, we synthesized and tested a group of C1-substituted acylhydrazone ß-carboline analogues 9a-o and 10a-o for their effectiveness against Valsa mali, Fusarium solani, Fusarium oxysporum, and Fusarium graminearum. Their compositions were analyzed using different spectral techniques, such as 1H/13C NMR and HRMS, with the structure of 9l being additionally confirmed through X-ray diffraction. The antifungal evaluation showed that, among all the target ß-carboline analogues, compounds 9n and 9o exhibited more promising and broad-spectrum antifungal activity than the commercial pesticide hymexazol. Several intriguing findings regarding structure-activity relationships (SARs) were examined. In addition, the cytotoxicity test showed that these acylhydrazone ß-carboline analogues with C1 substitutions exhibit a preference for fungi, with minimal harm to healthy cells (LO2). The reported findings provide insights into the development of ß-carboline analogues as new potential antifungal agents.

Identification of Biomarkers Associated with Phyllosticta citricarpa Tolerance.

Citrus black spot (CBS) is a fungal disease caused by Phyllosticta citricarpa Kiely, (McAlpine Van der Aa), with most cultivars being susceptible to infection. Currently, disease control is based on the application of protective fungicides, which is restricted due to resistance, health and environmental concerns. Although using natural products for disease management is gaining momentum, more advances are required. This study obtained the metabolic profiles of the essential oil and cuticular waxes of two citrus cultivars with a varying susceptibility to CBS infection using gas chromatography-mass spectrometry. A multivariate data analysis identified possible biomarker compounds that contributed to the difference in susceptibility between the two cultivars. Several identified biomarkers were tested in vitro for their antifungal properties against P. citricarpa. Two biomarkers, propanoic acid and linalool, were able to completely inhibit pathogen growth at 750 mg/L and 2000 mg/L, respectively.

The Impact of Cyclodextrins on the Physiology of Candida boidinii: Exploring New Opportunities in the Cyclodextrin Application.

Cyclodextrins, commonly used as excipients in antifungal formulations to improve the physicochemical properties and availability of the host molecules, have not been systematically studied for their effects and bioactivity without a complex active substance. This paper evaluates the effects of various cyclodextrins on the physiology of the test organism Candida boidinii. The research examines their impact on yeast growth, viability, biofilm formation and morphological changes. Native ACD, BCD, randomly methylated α- and ß-CD and quaternary ammonium α-CD and ß-CD were investigated in the 0.5-12.5 mM concentration range in both static and dynamic systems. The study revealed that certain cyclodextrins exhibited notable antifungal effects (up to ~69%) in dynamic systems; however, the biofilm formation was enhanced in static systems. The magnitude of these effects was influenced by several variables, including the size of the internal cavity, the concentration and structure of the cyclodextrins, and the contact time. Furthermore, the study found that CDs exhibited distinct effects in both static and dynamic systems, potentially related to their tendency to form aggregates. The findings suggest that cyclodextrins may have the potential to act as antifungal agents or growth promoters, depending on their structure and surrounding environments.

Identification of chitinase from Bacillus velezensis strain S161 and its antifungal activity against Penicillium digitatum.

Previous studies have demonstrated the presence of chitinase in Bacillus velezensis through extensive genomic sequencing and experimental analyses. However, the detailed structure, functional roles, and antifungal activity of these chitinases remain poorly characterized. In this study, genomic screening identified three genes-chiA, chiB, and lpmo10-associated with chitinase degradation in B. velezensis S161. These genes encode chitinases ChiA and ChiB, and lytic polysaccharide monooxygenase LPMO10. Both ChiA and ChiB contain two CBM50 binding domains and one catalytic domain, whereas LPMO10 includes a signal peptide and a single catalytic domain. The chitinases ChiA, its truncated variant ChiA2, and ChiB were heterologously expressed in Escherichia coli. The purified enzymes efficiently degraded colloidal chitin and inhibited the spore germination of Penicillium digitatum. Notably, even after losing one CBM50 domain, the resultant enzyme, consisting of the remaining CBM50 domain and the catalytic domain, maintained its colloidal chitin hydrolysis and antifungal activity, indicating commendable stability. These results underscore the role of B. velezensis chitinases in suppressing plant pathogenic fungi and provide a solid foundation for developing and applying chitinase-based biocontrol strategies.