Inhibition Of Fungal Growth Research Articles

Urtica dioica and Dodonaea viscosa leaf extracts as eco-friendly bioagents against Alternaria alternata isolate TAA-05 from tomato plant

One of the tomato’s acutely devastating diseases is Alternaria leaf spot, lowering worldwide tomato production. In this study, one fungal isolate was isolated from tomatoes and was assigned to Alternaria alternata TAA-05 upon morphological and molecular analysis of the ITS region and 18SrRNA, endoPG, Alt a1, and gapdh genes. Also, Urtica dioica and Dodonaea viscosa methanol leaf extracts (MLEs) were utilized as antifungal agents in vitro and compared to Ridomil, a reference chemical fungicide. The in vitro antifungal activity results revealed that Ridomil (2000 µg/mL) showed the highest fungal growth inhibition (FGI) against A. alternata (96.29%). Moderate activity was found against A. alternata by D. viscosa and U. dioica MLEs (2000 µg/mL), with an FGI value of 56.67 and 54.81%, respectively. The abundance of flavonoid and phenolic components were identified by HPLC analysis in the two plant extracts. The flavonoid compounds, including hesperidin, quercetin, and rutin were identified using HPLC in D. viscosa MLE with concentrations of 11.56, 10.04, and 5.14 µg/mL of extract and in U. dioica MLE with concentrations of 12.45, 9.21, and 5.23 µg/mL, respectively. α-Tocopherol and syringic acid, were also identified in D. viscosa MLE with concentrations of 26.13 and 13.69 µg/mL, and in U. dioica MLE, with values of 21.12 and 18.33 µg/mL, respectively. Finally, the bioactivity of plant extracts suggests that they play a crucial role as antifungal agents against A. alternata. Some phenolic chemicals, including coumaric acid, caffeic acid, ferulic acid, and α-tocopherol, have shown that they may be utilized as environmentally friendly fungicidal compounds.

Polyaniline-coated nanoparticles of zinc oxide and copper oxide as antifungal agents against Aspergillus parasiticus.

Aspergillus parasiticus (A. parasiticus) is known for producing aflatoxins and is a major threat to the food industry. Green synthesis of nanoparticles (NPs) is a cost-effective and environment-friendly approach. A variety of NPs have been explored as antifungal agents; however, their antifungal characteristics need to be further enhanced to compete with traditional fungicides. The present work describes the green synthesis of ZnO and CuO NPs by precipitation method using aqueous leaf extract of Manilkara zapota and their surface modification through polyaniline (PANI). Still, there is no published study on the application of PANI-coated particles as antifungal agents against A. parasiticus and hence was the focus of this work. The polymer-coated NPs were synthesized, characterized, and investigated for their antifungal properties against A. parasiticus. Textural and structural characterization of PANI-coated and non-coated ZnO and CuO NPs were confirmed through FT-IR, SEM, and XRD techniques. The PANI-coated NPs presented higher fungal growth inhibition (%) as compared to the non-coated ones. The maximum inhibition of 77 ± 2% (n = 3) was shown by PANI/ZnO NPs at a concentration of 12 mmol L−1 and 72 h of incubation. The non-coated NPs presented a lower inhibition rate with respect to their coated NPs, thus justifying the role of polymeric coating in improving antifungal efficiency.

Phytochemical profiling of Piper crocatum and its antifungal activity as Lanosterol 14 alpha demethylase CYP51 inhibitor: a review

Mycoses or fungal infections are a general health problem that often occurs in healthy and immunocompromised people in the community. The development of resistant strains in Fungi and the incidence of azole antibiotic resistance in the Asia Pacific which reached 83% become a critical problem nowadays. To control fungal infections, substances and extracts isolated from natural resources, especially in the form of plants as the main sources of drug molecules today, are needed. Especially from Piperaceae, which have long been used in India, China, and Korea to treat human ailments in traditional medicine. The purpose of this review was to describe antifungal activity from Piper crocatum and its phytochemical profiling against lanosterol 14 alpha demethylase CYP51. The methods used search databases from Google Scholar to find the appropriate databases using Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) flow diagram as a clinical information retrieval method. From 1,150,000 results search by database, there were 73 selected articles to review. The review shows that P. crocatum contains flavonoids, tannins, terpenes, saponins, polyphenols, eugenol, alkaloids, quinones, chavibetol acetate, glycosides, triterpenoids or steroids, hydroxychavikol, phenolics, glucosides, isoprenoids, and non-protein amino acids. Its antifungal mechanisms in fungal cells occur due to ergosterol especially lanosterol 14 alpha demethylase CYP51 inhibition as a result of 5,6 desaturase (ERG3) downregulation. P. crocatum has an antifungal activity by its phytochemical profiling that act against fungi by inhibiting the fungal cytochrome P 450 pathway, make damaging cell membranes, fungal growth inhibition, morphological changes, and fungal cell lysis.

Suppression of Chitin-Triggered Immunity by a New Fungal Chitin-Binding Effector Resulting from Alternative Splicing of a Chitin Deacetylase Gene.

Phytopathogenic fungi have evolved mechanisms to manipulate plant defences, such as chitin-triggered immunity, a plant defensive response based on the recognition of chitin oligomers by plant-specific receptors. To cope with chitin resistance, fungal pathogens have developed different strategies to prevent chitin recognition, such as binding, breaking, or modifying immunogenic oligomers. In powdery mildew fungi, the activity of chitin deacetylase (CDA) is crucial for this purpose, since silencing of the CDA gene leads to a rapid activation of chitin signalling and the subsequent suppression of fungal growth. In this work, we have identified an unusually short CDA transcript in Podosphaera xanthii, the cucurbit powdery mildew pathogen. This transcript, designated PxCDA3, appears to encode a truncated version of CDA resulting from an alternative splicing of the PxCDA gene, which lacked most of the chitin deacetylase activity domain but retained the carbohydrate-binding module. Experiments with the recombinant protein showed its ability to bind to chitin oligomers and prevent the activation of chitin signalling. Furthermore, the use of fluorescent fusion proteins allowed its localization in plant papillae at pathogen penetration sites. Our results suggest the occurrence of a new fungal chitin-binding effector, designated CHBE, involved in the manipulation of chitin-triggered immunity in powdery mildew fungi.

Endophytic bacterial strain,Brevibacillus brevis-mediated green synthesis of copper oxide nanoparticles, characterization, antifungal,in vitrocytotoxicity, and larvicidal activity

AbstractThe biomass filtrate containing various metabolites of endophytic bacterial strain,Brevibacillus brevisPI-5 was used as a biocatalyst for reducing and stabilizing copper oxide nanoparticles (CuO-NPs). UV-Vis spectroscopy, Fourier transform infrared, transmission electron microscopy, scanning electron microscopy with energy-dispersive X-ray (SEM-EDX), X-ray diffraction, and X-ray photoelectron spectroscopy were used for CuO-NPs characterization. A spherical, well-dispersed, and crystallographic structure with sizes of 2–28 nm was formed. The SEM-EDX confirmed the presence of Cu and O with weight percentages of 27.62% and 48.88%, respectively. The biological activities including antifungal, anticancer, and larvicidal of synthesized CuO-NPs were assessed using the fungal radial growth inhibition, MTT assay method, and mortality percentages, respectively. The obtained data showed that the CuO-NPs exhibit high activity in a dose-dependent manner. The growth of three phytopathogenic fungi,Fusarium oxysporum, Alternaria alternata, andAspergillus nigerwas decreased by percentages of 64.5% ± 4.1%, 62.9% ± 0.3%, and 70.2% ± 2.3%, respectively at 300 µg·mL–1. Also, various clinicalCandidaspp. were successfully inhibited with varied zones of inhibition and minimum inhibitory concentration values in ranges of 6.25–50 µg·mL–1. Thein vitrocytotoxicity exhibits target-orientation to breast cancer cells (T47D) at low concentration compared to normal cells (HFB4) with IC50values of 122.3 ± 5.4 and 229.9 ± 5.7 μg·mL–1, respectively. The mortality percentages of I, II, III, and IV instar larvae ofCulex antennatuswere 60% ± 1.4%, 43.1% ± 1.1%, 36.2% ± 1%, and 32.1% ± 0.9%, at 10 mg·L–1and increased to 86.9% ± 2.1%, 68.1% ± 1.7%, 64.4% ± 1.9%, and 53.1% ± 1.4% at 50 mg·L–1, respectively.

Biogenesis of nanoparticles with inhibitory effects on aflatoxin B1 production by Aspergillus flavus

BackgroundFungal nanofactories have been utilized to synthesize silver and gold nanoparticles. This study was designed to mycosynthesize and characterize silver and gold nanoparticles (AgNPs and AuNPs) and to study their effect on aflatoxin B1 production by Aspergillus flavus. ResultsSilver and gold nanoparticles were synthesized by endophytic Aspergillus versicolor and then analyzed by UV–vis spectroscopy. The results revealed surface plasmon resonance peaks at 432 and 536 nm for Ag and Au nanoparticles, respectively. The obtained transmission electron microscopy results revealed the fashioning of spherical AgNPs and spherical and hexagonal AuNPs with a mean particle magnitude of 5–37 and 37–62 nm, respectively. X-ray diffraction showed the typical face-centered cubic structure of the mycosynthesized Ag and Au nanoparticles. An in vitro investigation showed that AgNPs, AuNPs, and their mixture at different concentrations (10000, 5000, 3000, 1000, 750, 500, 250, and 125 µg/mL) could inhibit or reduce the outgrowth and production of aflatoxin B1 (AFB1) by A. flavus. The concentration that showed no AFB1 production was less than those for the inhibition of fungal growth. AgNPs, AuNPs, and their mixture also exhibited promising antiradical scavenging activity. ConclusionsThe use of fungi in the metallic nanoparticle’s fabrication and the utilization of mycosynthesized nanoparticles is promising as a substitute of chemicals to control antiaflatoxigenic fungi.How to cite: Sheikh H, Awad MF. Biogenesis of nanoparticles with inhibitory effects on aflatoxin B1 production by Aspergillus flavus. Electron J Biotechnol 2022;60. https://doi.org/10.1016/j.ejbt.2022.09.003.

Molecular dissection of rose and Botrytis cinerea pathosystems affected by ethylene

Botrytis cinerea (B. cinerea) is a necrotrophic pathogen that causes significant growth and postharvest commercial losses in cut roses. Postharvest disease severity is affected by ethylene levels during transport and storage conditions. In this study, we identified the relationship between ethylene, fungal growth, and ethylene inhibitors during B. cinerea infection in cut ‘Pink Beauty’ roses. The results suggest that cut rose susceptibility to gray mold disease is associated with the developmental stage of flowers, especially the level of senescence, which is stimulated by ethylene biosynthesis in petals. The mRNA levels of ethylene biosynthesis genes in petals were related to the severity of gray mold; however, their expression levels decreased when the cut roses were completely macerated by B. cinerea. B. cinerea infections in cut flowers activated ethylene biosynthesis and signaling pathways, leading to the activation of RhERFs in the petals. Ethylene regulated the development of B. cinerea infections in the cut flowers directly by binding to the receptors or indirectly by promoting the ethylene response in the host tissues. The suppression of ethylene responses in petals and inhibition of the fungal histidine kinase receptor of B. cinerea by 1-methylcylopropene (1-MCP) made cut rose flowers resistant to such necrotrophic pathogens. We also established a working model for ethylene binding and plant and fungus actions in the rose-B. cinerea pathosystem. Understanding the relationship between ethylene and gray mold disease in cut roses and the interaction between ethylene inhibitors and B. cinerea will help improve postharvest treatments for reducing B. cinerea damage in cut flowers.

Associated bacteria of a pine sawyer beetle confer resistance to entomopathogenic fungi via fungal growth inhibition

BackgroundThe entomopathogenic Beauveria bassiana is a popular fungus used to control the Japanese pine sawyer, Monochamus alternatus Hope, the key vector of pine wood nematode (Bursaphelenchus xylophilus) that is the causal agent of pine wilt disease, resulting in devastating losses of pines in China and Portugal. However, recent studies have demonstrated that some insect-associated bacteria might decrease fungal toxicity and further undermine its biological control efficacy against M. alternatus. Thus, it is of great significance to uncover whether and how associated bacteria of M. alternatus become involved in the infection process of B. bassiana.ResultsHere, we show that axenic M. alternatus larvae died significantly faster than non-axenic larvae infected by four increasing concentrations of B. bassiana spores (Log-rank test, P < 0.001). The infection of B. bassiana significantly changed the richness and structure of the beetle-associated bacterial community both on the cuticle and in the guts of M. alternatus; meanwhile, the abundance of Pseudomonas and Serratia bacteria were significantly enriched as shown by qPCR. Furthermore, these two bacteria genera showed a strong inhibitory activity against B. bassiana (One-way ANOVA, P < 0.001) by reducing the fungal conidial germination and growth rather than regulating host immunity.ConclusionsThis study highlights the role of insect-associated bacteria in the interaction between pest insects and entomopathogenic fungi, which should be taken into consideration when developing microbial-based pest control strategies.

Mechanism of Antifungal Action of Monoterpene Isoespintanol against Clinical Isolates of Candida tropicalis.

The growing increase in infections by Candida spp., non-albicans, coupled with expressed drug resistance and high mortality, especially in immunocompromised patients, have made candidemia a great challenge. The efficacy of compounds of plant origin with antifungal potential has recently been reported as an alternative to be used. Our objective was to evaluate the mechanism of the antifungal action of isoespintanol (ISO) against clinical isolates of Candida tropicalis. Microdilution assays revealed fungal growth inhibition, showing minimum inhibitory concentration (MIC) values between 326.6 and 500 µg/mL. The eradication of mature biofilms by ISO was between 20.3 and 25.8% after 1 h of exposure, being in all cases higher than the effect caused by amphotericin B (AFB), with values between 7.2 and 12.4%. Flow cytometry showed changes in the permeability of the plasma membrane, causing loss of intracellular material and osmotic balance; transmission electron microscopy (TEM) confirmed the damage to the integrity of the plasma membrane. Furthermore, ISO induced the production of intracellular reactive oxygen species (iROS). This indicates that the antifungal action of ISO is associated with damage to membrane integrity and the induction of iROS production, causing cell death.

Insights on biorational potential of Ocimum gratissimum essential oil and its binary combination with monoterpene phenol for control of rice weevil (Sitophilus oryzae) and aflatoxigenic fungi.

Food grain storage is a difficult task due to insect infestation and subsequent mycotoxin contaminations which adversely affects the nutritional quality of grains and leading to economic loss. Current research focuses on contact and fumigant toxicity effects of essential oils (EO) and aroma compounds against Sitophilus oryzae and growth inhibition of aflatoxigenic fungi. The EO of Ocimum gratissimum comprised of thymol (46.8%), γ-terpinene (14.04%) along with o-cymene (11.76%). Also, Cymbopogon flexuosus rich in citral (76.3%) and geraniol (84.6%) and Cymbopogon nardus having geraniol (49.24%) and geranyl acetate (20.9%) were all evaluated using a dose of 25 μL (Conc∼833.3 μL/L air) against S. oryzae. All the compounds showed significant mortality (>95%) at 24 h of exposure. The insecticidal property of O. gratissimum oil chemotype showed a strong contact and fumigant toxicity against S. oryzae at a highest dose of 25 μL (Conc∼833.3 μL/L air) within 24 h. It has been further evaluated on three aflatoxigenic fungal strains which showed reduction in growth and aflatoxin content (Aflatoxin B and G), which was markedly reduced upon the treatment. The binary mixture interaction of O. gratissimum oil with monoterpene phenol (carvacrol) was assessed and the specific binary mixture of 80:20 ratio (having additive property) acts as a contact insecticide with 100% mortality. Hence, essential oil of less explored Ocimum species (O. gratissimum) and its binary mixture could be deployed as potential biorational for control of rice weevil (Sitophilus oryzae) and aflatoxigenic Aspergillus spp.

Efecto aditivo de tratamiento alternativo al control químico de Botrytis cinerea en arándanos

The blueberry crop is mainly attacked by the phytopathogen Botrytis cinerea, being very aggressive for this plant, showing resistance to synthetic fungicides. Non-chemical alternatives such as chitosan and salicylic acid have been proposed for its control. Therefore, the objective of this study was to evaluate the combination of these compounds for the control of Botrytis cinerea. The in vitro evaluation showed percentages of fungal growth inhibition of 60% and 100% inhibition of sporulation and germination of the phytopathogen. The micrographs showed damage to fungal structures of B. cinerea under the application of the treatments due to the additive effect demonstrated by combining chitosan and salicylic acid. Likewise, there was a great reactivity when combining these compounds, favoring the attack on the phytopathogen and increasing the in vivo effect by reducing the decomposition rate of blueberries by 60% compared to the control.

Comparative Study on Phytochemical Properties and Antifungal Activities of Different Plant Extracts on Infected Fruit of Carica papaya

The comparative studies of phytochemical properties and antifungal activities of different plant extracts; Ageratum conyzoides L., Phyllanthus amarus Schum. &amp; Thonn, Senna alata (L.) Roxb. and Mangifera indica L. on infected fruit of Carica papaya was carried out using standard methods for analysis of all the tested parameters. The test was conducted using the selected plant extracts at five different concentrations (100 - 500mg/ml) against the isolated fungi. Molecular analysis was done to identify the isolated fungi. The results of the qualitative phytochemical screening revealed the presence of alkaloid, tannins, saponins, phenols and flavonoid in all the plant extracts. The quantitative phytochemical screening results showed varying quantities of alkaloids, tannins, saponins, flavonoids and phenols present in the extracts. The quantitative screening showed that A. conyzoides had the highest quantity of the constituents present in its extracts. Four fungal pathogens were isolated from paw-paw fruits and were identified as Rhizopus species, Aspergillus glavus, Aspergillus flavus and Penicillium species. The results of the antimicrobial assay on fungi isolated from infected pawpaw fruits showed that inhibition of fungal growth increased with a corresponding increase in concentration for all the fungal isolates. Penicillium species showed resistance to all the extracts. A. conyzoides showed the highest inhibition from 200mg/ml for the isolates followed by P.amarus. Molecular analysis identified the isolates as Rhizopus arrhizopus, R. delemar, R. oryzae and Aspergillus clavatus. The phylogenetic tree showed that Rhizopus oryzae, R. delemar, R arrhizus are closely related. A. conyzoides and P. amarus can be used to minimize the infection of paw-paw fruit by microbes.

Initial In Vitro Assessment of the Antifungal Activity of Aqueous Extracts from Three Invasive Plant Species

The development of new, safe, and effective methods of managing fungal pathogens is required. This study was conducted to perform an initial in vitro assessment of the antifungal activity of water-based plant extracts from three plants which are invasive in Egypt: Prosopis juliflora, Ipomoea carnea, and Leucaena leucocephala. These extracts were tested against three pathogenic fungi species that cause high crop losses in Egypt: Fusarium solani, Alternaria solani, and Colletotrichum circinans. Three extract concentrations, 10%, 20%, and 30%, were tested using a completely randomized design, with three replicates per treatment. Antifungal activity was determined based on the effects of plant extracts on fungal radial growth inhibition, average daily growth of fungi, spore formation, spore germination, and total biomass. Inhibition of the growth of fungal strains increased with increasing plant extract concentration, with the highest inhibitory rate at the 30% extract concentration. In addition, spore density, spore germination, and total biomass decreased significantly with increasing extract concentration. The three fungal pathogens differed in their inhibition and their response to these plant extracts. Prosopis juliflora had the highest inhibitory effect on the three fungal pathogens, compared to the extracts from the other two invasive plants. The results of this feasibility study indicate that P. juliflora extracts have high antifungal activity and follow-up in vivo assays should be conducted to determine their efficacy in the safe and sustainable management of these and other fungal pathogens.

Antifungal activity of lactic acid bacteria isolated from raw camel milk againts Alternaria alternata and identification of antifungal substance

The phytopathogenic filamentous fungi are responsible for the deterioration of various food products, such as fruits or vegetables, causing significant economic losses. They are also capable of producing several mycotoxins in infected plants and fruits.Lactic acid bacteria (LAB) are considered to be natural antagonists of these dangerous microorganisms. In the present study, 16 strains of LAB isolated from raw camel milk from various regions of Algeria, were the subject of phenotypic and genotypic identification, and they were tested for their antifungal activity. The well method was performed on five strains of lactic acid bacteria against four strains of the toxigenic and spoilage phytopathogenic fungus, Alternaria alternata, isolated from the stems, leaves, roots and fruits of tomatoes and carrots. A study of nature metabolites showed that these metabolites are stable at temperature, and keep the nature of the metabolites with the treatment with proteolytic enzymes such as Pepsin, Lysozyme and Trypsin, so their activity increases with increasing the pH of the culture medium. No loss of antifungal activity of the five selected strains was observed after treatment of the metabolites by heating at 4°C, 30°C, 45°C and 90°C. Internal transcribed spacer polymerase chain reaction (ITS-PCR) analysis and 16S rDNA sequencing were used to characterize and identify LAB isolates that showed varying levels of inhibition of fungal growth. Two strains of LAB, identified as Enterococcus lactis and E. faecium, had the strongest antifungal activity, suggesting potential application in food technology as bio-preservatives against phytopathogenic and food-altering fungi.

Application of Novel Biogenic nanoparticles for antimicrobial traits

Nanotechnology is a better approach to dealing with the current challenges of phytopathogens in agriculture and the environment. Nanoparticles (NPs) are less time-consuming, non-toxic and environmentally friendly and provide a high yield compared to conventional synthesis of NPs. Using plant growth promoting (PGP) bacterial strain for the synthesis of nanoparticles can route out the challenges of using chemical-based fertilizers and pesticides for agriculture. In our study, silver nanoparticles (AgNPs) were synthesized by using Burkholderia sp. 15B, which were further characterized by various physical techniques. All the techniques suggested the formation of biogenic NPs. We found that the bacteria-based NPs were able to hamper the growth of phytopathogenic fungi by more than 80%, as examined by the inhibition of fungal growth in the presence of green NPs. In addition, the synthesized NPs efficiently rescued seedlings from phytopathogenic fungal invasion. The results implicate the use of microorganism-mediated AgNPs as pesticides over chemical-based pesticides.

Safety Assessment of One Lactiplantibacillus plantarum Isolated from the Traditional Chinese Fermented Vegetables-Jiangshui.

Lactiplantibacillus plantarum is a kind of extensively utilized probiotic species, which plays a critical role in the prevention of pathogenic bacteria and development of functional probiotics. Our group previously isolated one Lactiplantibacillus from Jiang Shui, a traditional Chinese fermented vegetable, which remarkably inhibited the growth of Aspergillus flavus. Herein, the safety of this isolate was assessed to ensure its application feasibility in food industry. Firstly, the phenotypic analyses including tolerance to low pH and bile salt, aggregation ability, and hemolytic activity detection, indicated the isolate could survive and colonize in the gastrointestinal tract, without hemolysin activity. The susceptibilities of the isolate to eight antibiotics and the absence of most resistance genes were demonstrated by agar disk diffusion and PCR, respectively. Furthermore, no mortality or toxicity was observed in mice by in vivo tests using gross autopsy, hematology, serum biochemistry, and HE-staining. Taken together, this study demonstrated the safety of Lactiplantibacillus plantarum WYH as a probiotic strain in terms of phenotypic analyses, absence of antimicrobial resistance and toxin-related genes, as well as mice toxicity test, while supported the prospect of applying isolate in suppression of fungal growth and mycotoxin biosynthesis.

A Mycorrhizal Bacteria Strain Isolated From Polyporus umbellatus Exhibits Broad-Spectrum Antifungal Activity.

The microbes in the rhizosphere (or mycorrhizosphere) could promote plant growth, however, it is unclear whether mycorrhizosphere microbes could fight multiple fungal pathogens. In this study, twenty-one bacterial strains distributed in 6 genera, including 5 Pseudomonas strains, were isolated from mycorrhizal samples of Polyporus umbellatus that rely on other fungi during their life cycles. Further screening and pot experiments showed that the Pseudomonas strain ZL8 not only inhibited the growth of phytopathogenic fungi, but also promoted the growth of Salvia miltiorrhiza through inhibiting its wilting. In addition, strain ZL8 was found to have the ability to dissolve phosphate, produce IAA and siderophore. Nineteen compounds were identified from the fermentation broth of strain ZL8, of which 2,4-diacetylphloroglucinol (DAPG) had a significant inhibitory effect on phytopathogenic fungi with a minimum inhibitory concentration of 3.12–25 μg/mL. Molecular docking predicted that DAPG could bind to myosin I at two unique sites, which may be responsible to the inhibition of fungal growth. The evaluation results showed that strain ZL8 can be used to develop a dual-purpose biocontrol agents and biofertilizer. These results also provide new insights into the discovery and utilization of new resources for biocontrol agents and biolfertilizers.

Comparison of Current Peanut Fungicides Against Athelia rolfsii Through a Laboratory Bioassay of Detached Plant Tissues.

Southern stem rot of peanut, caused by Athelia rolfsii, is an important fungal disease that impacts peanut production worldwide. Foliar-applied fungicides are used to manage the disease, and several fungicides have been recently registered for southern stem rot control in peanuts. This study compared fungicidal, residual, and potential systemic activity of current fungicides against A. rolfsii using a laboratory bioassay. Peanut plants grown in the field were treated with eight fungicides approximately 90 days after planting, and plants were collected for the laboratory bioassay weekly for 5 weeks following application. Peanut plants were separated into the newest fully mature leaf present at sample collection, the second newest fully mature leaf present at the time of fungicide application, the upper stem, and the crown tissues. Each plant tissue was inoculated with A. rolfsii then incubated at 30°C for 2 days. Lesion length was measured, and percent inhibition of fungal growth by each fungicide relative to the control was calculated. All fungicides provided the greatest inhibition of A. rolfsii on leaf tissues that were present at the time of fungicide application, followed by the newly grown leaf and upper stem. Little inhibition occurred on the crown. Fungal inhibition decreased at similar rates over time for all fungicides tested. Succinate dehydrogenase inhibitors provided less basipetal protection of upper stems than quinone outside inhibitor or demethylation inhibitor fungicides. Properties of the fungicides characterized in this study, including several newly registered products, are useful for developing fungicide application recommendations to maximize their efficacy in controlling both foliar and soilborne peanut diseases.

Postantifungal Effect of Antifungal Drugs against Candida: What Do We Know and How Can We Apply This Knowledge in the Clinical Setting?

The study of the pharmacological properties of an antifungal agent integrates the drug pharmacokinetics, the fungal growth inhibition, the fungicidal effect and the postantifungal activity, laying the basis to guide optimal dosing regimen selection. The current manuscript reviews concepts regarding the postantifungal effect (PAFE) of the main classes of drugs used to treat Candida infections or candidiasis. The existence of PAFE and its magnitude are highly dependent on both the fungal species and the class of the antifungal agent. Therefore, the aim of this article was to compile the information described in the literature concerning the PAFE of polyenes, azoles and echinocandins against the Candida species of medical interest. In addition, the mechanisms involved in these phenomena, methods of study, and finally, the clinical applicability of these studies relating to the design of dosing regimens were reviewed and discussed. Additionally, different factors that could determine the variability in the PAFE were described. Most PAFE studies were conducted in vitro, and a scarcity of PAFE studies in animal models was observed. It can be stated that the echinocandins cause the most prolonged PAFE, followed by polyenes and azoles. In the case of the triazoles, it is worth noting the inconsistency found between in vitro and in vivo studies.

Nanoemulsification of Kaempferia galanga essential oil: Characterizations and molecular interactions explaining fungal growth suppression

Present study envisaged the development of nanoemulsions (NEs) based on essential oil (EO) of Kaempferia galanga using biosurfactant, saponin. Aromatic components of the distilled EO were characterized in GC-MS and the oil was formulated to prepare NEs with saponin at three different concentrations (0.5%, 1.0% and 2.0%) using ultrasonic acoustic energy at three individual time points (3, 5 and 10 min). NEs prepared with ≥ 1% saponin solution with ≥ 10 min ultrasonication were found stable even after accelerated storage condition at 54 ± 1 °C for 14 days. Briefly, NEs at 400 µg/mL concentration, showed hydrodynamic droplet diameter of 71.68 nm with the corresponding PDI 0.52 and zeta potential − 20.05 mV. TEM images confirmed the spherical morphology and droplet diameters. NEs exhibited excellent efficacy against A. flavus 2547 (32.3 µg/mL) followed by A. flavus 2838 (45.6 µg/mL), A. flavus 8601 (56.2 µg/mL) and A. flavus 6641 (69.7 µg/mL). Molecular modelling studies revealed the most promising binding complexes of 6IV7-ethyl-p-methoxycinnamate (−56.22 kcal/mol), the key component responsible for interfering functional properties of the native ligand. Additive interaction effect of 4QBJ-pentadecane (−50.15 kcal/mol) and 6JOH-ethyl-p-methoxycinnamate (−45.91 kcal/mol) attributed to the extraordinary favourable binding energy for non-bonded covalent and lipophilic interactions towards the selective target proteins.