The effect of DMSO on Saccharomyces cerevisiae yeast with different energy metabolism and antioxidant status.

We studied the effect of dimethyl sulfoxide (DMSO) on the biochemical and physiological parameters of S. cerevisiae yeast cells with varied energy metabolism and antioxidant status. The wild-type cells of varied genetic backgrounds and their isogenic mutants with impaired antioxidant defences (Δsod mutants) or response to environmental stress (ESR) (Δmsn2, Δmsn4 and double Δmsn2msn4 mutants) were used. Short-term exposure to DMSO even at a wide range of concentrations (2-20%) had little effect on the metabolic activity of the yeast cells and the stability of their cell membranes, but induced free radicals production and clearly altered their proliferative activity. Cells of the Δsod1 mutant showed greater sensitivity to DMSO in these conditions. DMSO at concentrations from 4 to 10-14% (depending on the strain and genetic background) activated the ESR programme. The effects of long-term exposure to DMSO were mainly depended on the type of energy metabolism and antioxidant system efficiency. Yeast cells with reduced antioxidant system efficiency and/or aerobic respiration were more susceptible to the toxic effects of DMSO than cells with a wild-type phenotype and respiro-fermentative or fully fermentative metabolism. These studies suggest a key role of stress response programs in both the processes of cell adaptation to small doses of this xenobiotic and the processes related to its toxicity resulting from large doses or chronic exposure to DMSO.

Curcumin Inhibits TORC1 and Prolongs the Lifespan of Cells with Mitochondrial Dysfunction.

Aging is an inevitable biological process that contributes to the onset of age-related diseases, often as a result of mitochondrial dysfunction. Understanding the mechanisms behind aging is crucial for developing therapeutic interventions. This study investigates the effects of curcumin on postmitotic cellular lifespan (PoMiCL) during chronological aging in yeast, a widely used model for human postmitotic cellular aging. Our findings reveal that curcumin significantly prolongs the PoMiCL of wildtype yeast cells, with the most pronounced effects observed at lower concentrations, indicating a hormetic response. Importantly, curcumin also extends the lifespan of postmitotic cells with mitochondrial deficiencies, although the hormetic effect is absent in these defective cells. Mechanistically, curcumin inhibits TORC1 activity, enhances ATP levels, and induces oxidative stress. These results suggest that curcumin has the potential to modulate aging and offer therapeutic insights into age-related diseases, highlighting the importance of context in its effects.

Exploring the Anticancer Potential of Phenolic nor-Triterpenes from Celastraceae Species.

To explore new compounds with antitumour activity, fifteen phenolic nor-tripterpenes isolated from Celastraceae species, Maytenus jelskii, Maytenus cuzcoina, and Celastrus vulcanicola, have been studied. Their chemical structures were elucidated through spectroscopic and spectrometric techniques, resulting in the identification of three novel chemical compounds. Evaluation on human tumour cell lines (A549 and SW1573, non-small cell lung; HBL-100 and T-47D, breast; HeLa, cervix, and WiDr, colon) revealed that three compounds, named 6-oxo-pristimerol, demethyl-zeylasteral, and zeylasteral, exhibited significant activity (GI50 ranging from 0.45 to 8.6 µM) on at least five of the cell lines tested. Continuous live cell imaging identified apoptosis as the mode of action of selective cell killing in HeLa cells. Furthermore, their effect on a drug-sensitive Saccharomyces cerevisiae strain has been investigated to deepen on their mechanism of action. In dose-response growth curves, zeylasteral and 7α-hydroxy-blepharodol were markedly active. Additionally, halo assays were conducted to assess the involvement of oxidative stress and/or mitochondrial function in the anticancer profile, ruling out these modes of action for the active compounds. Finally, we also delve into the structure-activity relationship, providing insights into how the molecular structure of these compounds influences their biological activity. This comprehensive analysis enhances our understanding of the therapeutic potential of this triterpene type and underscores its relevance for further research in this field.

Distinguishing mutants that resist drugs via different mechanisms by examining fitness tradeoffs.

There is growing interest in designing multidrug therapies that leverage tradeoffs to combat resistance. Tradeoffs are common in evolution and occur when, for example, resistance to one drug results in sensitivity to another. Major questions remain about the extent to which tradeoffs are reliable, specifically, whether the mutants that provide resistance to a given drug all suffer similar tradeoffs. This question is difficult because the drug-resistant mutants observed in the clinic, and even those evolved in controlled laboratory settings, are often biased towards those that provide large fitness benefits. Thus, the mutations (and mechanisms) that provide drug resistance may be more diverse than current data suggests. Here, we perform evolution experiments utilizing lineage-tracking to capture a fuller spectrum of mutations that give yeast cells a fitness advantage in fluconazole, a common antifungal drug. We then quantify fitness tradeoffs for each of 774 evolved mutants across 12 environments, finding these mutants group into classes with characteristically different tradeoffs. Their unique tradeoffs may imply that each group of mutants affects fitness through different underlying mechanisms. Some of the groupings we find are surprising. For example, we find some mutants that resist single drugs do not resist their combination, while others do. And some mutants to the same gene have different tradeoffs than others. These findings, on one hand, demonstrate the difficulty in relying on consistent or intuitive tradeoffs when designing multidrug treatments. On the other hand, by demonstrating that hundreds of adaptive mutations can be reduced to a few groups with characteristic tradeoffs, our findings may yet empower multidrug strategies that leverage tradeoffs to combat resistance. More generally speaking, by grouping mutants that likely affect fitness through similar underlying mechanisms, our work guides efforts to map the phenotypic effects of mutation.

Mutations in an organism's DNA make the individual more likely to survive and reproduce in its environment, passing on its mutations to the next generation. Mutations can alter the proteins that a gene codes for in many ways. This leads to a situation where seemingly similar mutations ­ such as two mutations in the same gene ­ can have different effects. For example, two different mutations could affect the primary function of the encoded protein in the same way but have different side effects. One mutation might also cause the protein to interact with a new molecule or protein. Organisms possessing one or the other mutation will thus have similar odds of surviving and reproducing in some environments, but differences in environments where the new interaction is important. In microorganisms, mutations can lead to drug resistance. If drug-resistant mutations have different side effects, it can be challenging to treat microbial infections, as drug-resistant pathogens are often treated with sequential drug strategies. These strategies rely on mutations that cause resistance to the first drug all having susceptibility to the second drug. But if similar seeming mutations can have diverse side effects, predictions about how they will respond to a second drug are more complicated. To address this issue, Schmidlin, Apodaca et al. collected a diverse group of nearly a thousand mutant yeast strains that were resistant to a drug called fluconazole. Next, they asked to what extent the fitness ­ the ability to survive and reproduce ­ of these mutants responded similarly to environmental change. They used this information to cluster mutations into groups that likely have similar effects at the molecular level, finding at least six such groups with unique trade-offs across environments. For example, some groups resisted only low drug concentrations, and others were unique in that they resisted treatment with two single drugs but not their combination. These diverse types of fluconazole-resistant yeast lineages highlight the challenges of designing a simple sequential drug treatment that targets all drug-resistant mutants. However, the results also suggest some predictability in how drug-resistant infections can evolve and be treated.

Isolate distribution and antifungal susceptibility of Saccharomyces cerevisiae in the national regional medical center of Southwest China for women and children during 2018-2023.

BACKGROUND: Saccharomyces cerevisiae has been considered a harmless yeast, but in recent years, increasing evidence has shown that it can cause disease in humans, especially invasive infections in infants/children and vulvovaginal infections in women. This study aimed to investigate the clinical information and antifungal susceptibility of clinical cases with S. cerevisiae and establish a foundation for the prevention and treatment of fungal infections. METHODS: This study was conducted from May 2018 to May 2023 at a national regional medical center in Southwest China for women and children. The demographic and clinical characteristics of patients isolated with S. cerevisiae were collected and analyzed. All the isolates were cultured on Sabouraud medium plates and identified by MALDI-TOF MS. The antifungal susceptibility of S. cerevisiae to 10 agents (amphotericin B, fluconazole, itraconazole, voriconazole, micafungin, caspofungin, terbinafine and 5-flucytosine) was determined via the microdilution broth method to determine the minimum inhibitory concentrations (MICs). RESULTS: A total of 75 cases of S. cerevisiae isolated from patients with vulvovaginal candidiasis (VVC, 44 cases), pneumonia (13 cases), or diarrhea (18 cases) were included after data review. The MICs of voriconazole and flucytosine for S. cerevisiae isolated from different body sites differed, with higher resistance in intestinal isolates. In this study, S. cerevisiae caused VVC, but there was no clear evidence that it was involved in pneumonia or diarrhea. Compared with those of Candida albicans, the primary pathogen of VVC, the MICs of fluconazole (11.96 ± 5.78 µg/mL vs. 67.64 ± 16.62 µg/mL, p = 0.002), itraconazole (0.77 ± 0.19 µg/mL vs. 2.31 ± 0.53 µg/mL, p = 0.008), voriconazole (0.22 ± 0.09 µg/mL vs. 5.02 ± 1.09 µg/mL, p < 0.001), and terbinafine (10.41 ± 0.84 µg/mL vs. 14.93 ± 4.77 µg/mL, p < 0.001) for S. cerevisiae (isolated from the genital tract) were significantly lower, while those of micafungin (0.14 ± 0.01 µg/mL vs. 0.06 ± 0.01 µg/mL, p < 0.001) and caspofungin (0.27 ± 0.04 µg/mL vs. 0.06 ± 0.01 µg/mL, p < 0.001) were significantly greater. CONCLUSION: Azoles remain the recommended regimen for S. cerevisiae-related VVC, and the use of amphotericin B vaginal effervescent tablets could be considered for the treatment of azole-resistant isolates. The antifungal susceptibility of S. cerevisiae varies according to the isolated source, and the pathogenicity trend of S. cerevisiae should be studied.

Cytotoxicity assessment and antimicrobial effects of cell-free supernatants from probiotic lactic acid bacteria and yeast against multi-drug resistant Escherichia coli.

The antibacterial, antibiofilm, and cytotoxicity activity of cell-free supernatants (CFSs) from probiotics, including Lactobacillus plantarum, Bifidobacterium bifidum, and Saccharomyces cerevisiae against multi-drug resistant Escherichia coli evaluated in current research. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the CFSs were determined by analyzing inhibition zone formation using agar disk diffusion for antibacterial activity, microtiter plate for biofilm analysis, and auto-aggregation were done. CFSs substances were analyzed by GC-MS. The MTT assay on HEK293 cells investigated CFS's influence on cell viability. CFSs were examined for biofilm-related virulence genes, including aggR and fimH using real-time polymerase chain reaction (real-time PCR). All CFSs had bacteriostatic and bactericidal effects. The B. bifidum exhibited the highest antibiofilm activity compared to the others. Bifidobacterium bifidum, L. plantarum, and S. cerevisiae produce 19, 16, and 11 mm inhibition zones against E. coli, respectively. GC-MS indicated that Hydroxyacetone, 3-Hydroxybutyric acid, and Oxime-methoxy-phenyl-dominated CFSs from L. plantarum, B. bifidum, and S. cerevisiae CFSs, respectively. The MTT test demonstrated a cell viability rate of over 90%. Statistically, adding all CFSs lowered the relative expression of both aggR and fimH virulence genes.

A versatile yeast model identifies the pesticides cymoxanil and metalaxyl as risk factors for synucleinopathies.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons and the presence of Lewy bodies, which predominantly consist of aggregated forms of the protein alpha-synuclein (aSyn). While these aggregates are a pathological hallmark of PD, the etiology of most cases remains elusive. Although environmental risk factors have been identified, such as the pesticides dieldrin and MTPT, many others remain to be assessed and their molecular impacts are underexplored. This study aimed to identify pesticides that could enhance aSyn aggregation using a humanized yeast model expressing aSyn fused to GFP as a primary screening platform, which we validated using dieldrin. We found that the pesticides cymoxanil and metalaxyl induce aggregation of aSyn in yeast, which we confirmed also occurs in a model of aSyn inclusion formation using human H4 cells. In conclusion, our approach generated invaluable molecular data on the effect of pesticides, therefore providing insights into mechanisms associated with the onset and progression of PD and other synucleinopathies.

Improvement of Saccharomyces cerevisiae strain tolerance to vanillin through heavy ion radiation combined with adaptive laboratory evolution.

Vanillin is an inhibitor of lignocellulose hydrolysate, which can reduce the ability of Saccharomyces cerevisiae to utilize lignocellulose, which is an important factor limiting the development of the ethanol fermentation industry. In this study, mutants of vanillin-tolerant yeast named H6, H7, X3, and X8 were bred by heavy ion irradiation (HIR) combined with adaptive laboratory evolution (ALE). Phenotypic tests revealed that the mutants outperformed the original strain WT in tolerance, growth rate, genetic stability and fermentation ability. At 1.6 g/L vanillin concentration, the average OD600 value obtained for mutant strains was 0.95 and thus about 3.4-fold higher than for the wild-type. When the concentration of vanillin was 2.0 g/L, the glucose utilization rate of the mutant was 86.3 % within 96 h, while that of the original strain was only 70.0 %. At this concentration of vanillin, the mitochondrial membrane potential of the mutant strain recovered faster than that of the original strain, and the ROS scavenging ability was stronger. We analyzed the whole transcriptome sequencing map and the whole genome resequencing of the mutant, and found that DEGs such as FLO9, GRC3, PSP2 and SWF1, which have large differential expression multiples and obvious mutation characteristics, play an important role in cell flocculation, rDNA transcription, inhibition of DNA polymerase mutation and protein palmitoylation. These functions can help cells resist vanillin stress. The results show that combining HIR with ALE is an effective mutagenesis strategy. This approach can efficiently obtain Saccharomyces cerevisiae mutants with improved vanillin tolerance, and provide reference for obtaining robust yeast strains with lignocellulose inhibitor tolerance.

Rational selection of morphological phenotypic traits to extract essential similarities in chemical perturbation in the ergosterol pathway.

Terbinafine, fluconazole, and amorolfine inhibit fungal ergosterol synthesis by acting on their target enzymes at different steps in the synthetic pathway, causing the accumulation of various intermediates. We found that the effects of these three in- hibitors on yeast morphology were different. The number of morphological parameters commonly altered by these drugs was only approximately 6% of the total. Using a rational strategy to find commonly changed parameters,we focused on hidden essential similarities in the phenotypes possibly due to decreased ergosterol levels. This resulted in higher apparent morphological similarity. Improvements in morphological similarity were observed even when canonical correlation analysis was used to select biologically meaningful morphological parameters related to gene function. In addition to changes in cell morphology, we also observed differences in the synergistic effects among the three inhibitors and in their fungicidal effects against pathogenic fungi possibly due to the accumulation of different intermediates. This study provided a comprehensive understanding of the properties of inhibitors acting in the same biosynthetic pathway.

Insights into the antifungal mechanism of Bacillus subtilis cyclic lipopeptide iturin A mediated by potassium ion channel.

Fungal infections pose severe and potentially lethal threats to plant, animal, and human health. Ergosterol has served as the primary target for developing antifungal medications. However, many antifungal drugs remain highly toxic to humans due to similarity in cell membrane composition between fungal and animal cells. Iturin A, lipopeptide produced by Bacillus subtilis, efficiently inhibit various fungi, but demonstrated safety in oral administration, indicating the existence of targets different from ergosterol. To pinpoint the exact antifungal target of iturin A, we used homologous recombination to knock out and overexpress erg3, a key gene in ergosterol synthesis. Saccharomyces cerevisiae and Aspergillus carbonarius were transformed using the LiAc/SS-DNNPEG and Agrobacterium-mediated transformation (AMT), respectively. Surprisingly, increasing ergosterol content did not augment antifungal activity. Furthermore, iturin A's antifungal activity against S. cerevisiae was reduced while it pre-incubation with voltage-gated potassium (Kv) channel inhibitor, indicating that Kv activation was responsible for cell death. Iturin A was found to activate the Kv protein, stimulating K+ efflux from cell. In vitro tests confirmed interaction between iturin A and Kv protein. This study highlights Kv as one of the precise targets of iturin A in its antifungal activity, offering a novel target for the development of antifungal medications.

The novel ribosome biogenesis inhibitor usnic acid blocks nucleolar pre-60S maturation.

The formation of new ribosomes is tightly coordinated with cell growth and proliferation. In eukaryotes, the correct assembly of all ribosomal proteins and RNAs follows an intricate scheme of maturation and rearrangement steps across three cellular compartments: the nucleolus, nucleoplasm, and cytoplasm. We demonstrate that usnic acid, a lichen secondary metabolite, inhibits the maturation of the large ribosomal subunit in yeast. We combine biochemical characterization of pre-ribosomal particles with a quantitative single-particle cryo-EM approach to monitor changes in nucleolar particle populations upon drug treatment. Usnic acid rapidly blocks the transition from nucleolar state B to C of Nsa1-associated pre-ribosomes, depleting key maturation factors such as Dbp10 and hindering pre-rRNA processing. This primary nucleolar block rapidly rebounds on earlier stages of the pathway which highlights the regulatory linkages between different steps. In summary, we provide an in-depth characterization of the effect of usnic acid on ribosome biogenesis, which may have implications for its reported anti-cancer activities.

What's killing lab yeast around the world?

Multiple researchers are reporting toxic agar, but the ultimate culprit remains unclear.

Discovery of an antimalarial compound, burnettiene A, with a multidrug-sensitive Saccharomyces cerevisiae screening system based on mitochondrial function inhibitory activity.

In this paper, we describe our discovery of burnettiene A (1) as an antimalarial compound from the culture broth of Lecanicillium primulinum (current name: Flavocillium primulinum) FKI-6715 strain utilizing our original multidrug-sensitive yeast system. This polyene-decalin polyketide natural product was originally isolated as an antifungal active compound from Aspergillus burnettii. However, the antifungal activity of 1 has been revealed in only one fungal species, and the mechanism of action of 1 remains unknown. After the validation of mitochondrial function inhibitory of 1, we envisioned a new antimalarial drug discovery platform based on mitochondrial function inhibitory activity. We evaluated antimalarial activity and 1 showed antimalarial activity against Plasmodium falciparum FCR3 (chloroquine sensitive) and the K1 strain (chloroquine resistant). Our study revealed the utility of our original screening system based on a multidrug-sensitive yeast and mitochondrial function inhibitory activity for the discovery of new antimalarial drug candidates.

Natural variation in yeast reveals multiple paths for acquiring higher stress resistance.

BACKGROUND: Organisms frequently experience environmental stresses that occur in predictable patterns and combinations. For wild Saccharomyces cerevisiae yeast growing in natural environments, cells may experience high osmotic stress when they first enter broken fruit, followed by high ethanol levels during fermentation, and then finally high levels of oxidative stress resulting from respiration of ethanol. Yeast have adapted to these patterns by evolving sophisticated "cross protection" mechanisms, where mild 'primary' doses of one stress can enhance tolerance to severe doses of a different 'secondary' stress. For example, in many yeast strains, mild osmotic or mild ethanol stresses cross protect against severe oxidative stress, which likely reflects an anticipatory response important for high fitness in nature. RESULTS: During the course of genetic mapping studies aimed at understanding the mechanisms underlying natural variation in ethanol-induced cross protection against H2O2, we found that a key H2O2 scavenging enzyme, cytosolic catalase T (Ctt1p), was absolutely essential for cross protection in a wild oak strain. This suggested the absence of other compensatory mechanisms for acquiring H2O2 resistance in that strain background under those conditions. In this study, we found surprising heterogeneity across diverse yeast strains in whether CTT1 function was fully necessary for acquired H2O2 resistance. Some strains exhibited partial dispensability of CTT1 when ethanol and/or salt were used as mild stressors, suggesting that compensatory peroxidases may play a role in acquired stress resistance in certain genetic backgrounds. We leveraged global transcriptional responses to ethanol and salt stresses in strains with different levels of CTT1 dispensability, allowing us to identify possible regulators of these alternative peroxidases and acquired stress resistance in general. CONCLUSIONS: Ultimately, this study highlights how superficially similar traits can have different underlying molecular foundations and provides a framework for understanding the diversity and regulation of stress defense mechanisms.

Vitamin B5 metabolism is essential for vacuolar and mitochondrial functions and drug detoxification in fungi.

Fungal infections, a leading cause of mortality among eukaryotic pathogens, pose a growing global health threat due to the rise of drug-resistant strains. New therapeutic strategies are urgently needed to combat this challenge. The PCA pathway for biosynthesis of Co-enzyme A (CoA) and Acetyl-CoA (AcCoA) from vitamin B5 (pantothenic acid) has been validated as an excellent target for the development of new antimicrobials against fungi and protozoa. The pathway regulates key cellular processes including metabolism of fatty acids, amino acids, sterols, and heme. In this study, we provide genetic evidence that disruption of the PCA pathway in Saccharomyces cerevisiae results in a significant alteration in the susceptibility of fungi to a wide range of xenobiotics, including clinically approved antifungal drugs through alteration of vacuolar morphology and drug detoxification. The drug potentiation mediated by genetic regulation of genes in the PCA pathway could be recapitulated using the pantazine analog PZ-2891 as well as the celecoxib derivative, AR-12 through inhibition of fungal AcCoA synthase activity. Collectively, the data validate the PCA pathway as a suitable target for enhancing the efficacy and safety of current antifungal therapies.

Mechanism of azole resistance in Candida vulturna, an emerging multidrug resistant pathogen related with Candida haeumulonii and Candida auris.

BACKGROUND: Candida vulturna is an emerging pathogen belonging to the Metshnikowiaceae family together with Candida auris and Candida haemulonii species complex. Some strains of this species were reported to be resistant to several antifungal agents. OBJECTIVES: This study aims to address identification difficulties, evaluate antiungal susceptibilities and explore the molecular mechanisms of azole resistance of Candida vulturna. METHODS: We studied five C. vulturna clinical strains isolated in three Colombian cities. Identification was performed by phenotypical, proteomic and molecular methods. Antifungal susceptibility testing was performed following CLSI protocol. Its ERG11 genes were sequenced and a substitution was encountered in azole resistant isolates. To confirm the role of this substitution in the resistance phenotype, Saccharomyces cerevisiae strains with a chimeric ERG11 gene were created. RESULTS: Discrepancies in identification methods are highlighted. Sequencing confirmed the identification as C. vulturna. Antifungal susceptibility varied among strains, with four strains exhibiting reduced susceptibility to azoles and amphotericin B. ERG11 sequencing showed a point mutation (producing a P135S substitution) that was associated with the azole-resistant phenotype. CONCLUSIONS: This study contributes to the understanding of C. vulturna's identification challenges, its susceptibility patterns, and sheds light on its molecular mechanisms of azole resistance.

Synthesis and antifungal evaluation of novel triazole derivatives bearing a pyrazole-methoxyl moiety.

Life-threatening invasive fungal infections pose a serious threat to human health. A series of novel triazole derivatives bearing a pyrazole-methoxyl moiety were designed and synthesized in an effort to obtain antifungals with potent, broad-spectrum activity that are less susceptible to resistance. Most of these compounds exhibited moderate to excellent in vitro antifungal activities against Candida albicans SC5314 and 10,231, Cryptococcus neoformans 32,609, Candida glabrata 537 and Candida parapsilosis 22,019 with minimum inhibitory concentration (MIC) values of ≤0.125 µg/mL to 0.5 µg/mL. Use of recombinant Saccharomyces cerevisiae strains showed compounds 7 and 10 overcame the overexpression and resistant-related mutations in ERG11 of S. cerevisae and several pathogenic Candida spp. Despite being substrates of the C. albicans and Candida auris Cdr1 drug efflux pumps, compounds 7 and 10 showed moderate potency against five fluconazole (FCZ)-resistant fungi with MIC values from 2.0 µg/mL to 16.0 µg/mL. Growth kinetics confirmed compounds 7 and 10 had much stronger fungistatic activity than FCZ. For C. albicans, compounds 7 and 10 inhibited the yeast-to-hyphae transition, biofilm formation and destroyed mature biofilm more effectively than FCZ. Preliminary mechanism of action studies showed compounds 7 and 10 blocked the ergosterol biosynthesis pathway at Erg11, ultimately leading to cell membrane disruption. Further investigation of these novel triazole derivatives is also warranted by their predicted ADMET properties and low cytotoxicity.

Imidazolium-based ionic liquids disrupt saccharomyces cerevisiae cell membrane integrity.

Ionic liquids (ILs) are interesting chemical compounds that have a wide range of industrial and scientific applications. They have extraordinary properties, such as the tunability of many of their physical properties and, accordingly, their activities; and the ease of synthesis methods. Hence, they became important building blocks in catalysis, extraction, electrochemistry, analytics, biotechnology, etc. This study determined antifungal activities of various imidazolium-based ionic liquids against yeast Saccharomyces cerevisiae via minimum inhibitory concentration (MIC) estimation method. Increasing the length of the alkyl group attached to the imidazolium cation, enhanced the antifungal activity of the ILs, as well as their ability of the disruption of the cell membrane integrity. FTIR studies performed on the S. cerevisiae cells treated with the ILs revealed alterations in the biochemical composition of these cells. Interestingly, the alterations in fatty acid content occurred in parallel with the increase in the activity of the molecules upon the increase in the length of the attached alkyl group. This trend was confirmed by statistical analysis and machine learning methodology. The classification of antifungal activities based on FTIR spectra of S. cerevisiae cells yielded a prediction accuracy of 83%, indicating the pharmacy and medicine industries could benefit from machine learning methodology. Furthermore, synthesized ionic compounds exhibit significant potential for pharmaceutical and medical applications.

Membrane potential dynamics unveil the promise of bioelectrical antimicrobial susceptibility Testing (BeAST) for anti-fungal screening.

Membrane potential is a useful marker for antimicrobial susceptibility testing (AST) due to its fundamental roles in cell function. However, the difficulties associated with measuring the membrane potential in microbes restrict its broad application. In this study, we present bioelectrical AST (BeAST) using the model fungus Saccharomyces cerevisiae. Using fluorescent indicators [DiBAC4(3), ThT, and TMRM], we measured plasma and mitochondrial membrane-potential dynamics upon electric stimulation. We find that a 2.5 second electric stimulation induces hyperpolarization of plasma membrane lasting 20 minutes in vital S. cerevisiae, but depolarization in inhibited cells. The numerical simulation of FitzHugh-Nagumo model successfully recapitulates vitality-dependent dynamics. The model also suggests that the magnitude of plasma-membrane potential dynamics (PMD) correlates with the degree of inhibition. To test this prediction and to examine if BeAST can be used for assessing novel anti-fungal compounds, we treat cells with biogenic silver nanoparticles (bioAgNPs) synthesized using orange fruit flavonoids and Fusarium oxysporum. Comparing BeAST with optical density assay alongside various stressors, we show that PMD correlates with the magnitude of growth inhibitions. These results suggest that BeAST holds promise for screening anti-fungal compounds, offering a valuable approach to tackling antimicrobial resistance. IMPORTANCE: Rapid assessment of the efficacy of antimicrobials is important for optimizing treatments, avoiding misuse and facilitating the screening of new antimicrobials. The need for rapid antimicrobial susceptibility testing (AST) is growing with the rise of antimicrobial resistance. Here, we present bioelectrical AST (BeAST). Combining time-lapse microscopy and mathematical modeling, we show that electrically induced membrane potential dynamics of yeast cells correspond to the strength of growth inhibition. Furthermore, we demonstrate the utility of BeAST for assessing antimicrobial activities of novel compounds using biogenic silver nanoparticles.

Preparation, characterization and antioxidant and anticancerous potential of Quercetin loaded ß-glucan particles derived from mushroom and yeast.

ß-glucans are polysaccharides found in the cell walls of various fungi, bacteria and cereals. ß-glucan have been found to show various kinds of anti-inflammatory, antimicrobial, antidiabetic antioxidant and anticancerous activities. In the present study, we have isolated ß-glucan from the baker's yeast Saccharomyces cerevisiae and white button mushroom Agaricus bisporus and tested their antioxidant potential and anticancerous activity against prostate cancer cell line PC3. Particles were characterized with zeta sizer and further with FTIR that confirmed that the isolated particles are ß-glucan and alginate sealing made slow and sustained release of the Quercetin from the ß-glucan particles. Morphological analysis of the hollow and Quercetin loaded ß-glucan was performed with the SEM analysis and stability was analyzed with TGA and DSC analysis that showed the higher stability of the alginate sealed particles. Assessments of the antioxidant potential showed that Quercetin loaded particles were having higher antioxidant activity than hollow ß-glucan particles. Cell viability of the PC3 cells was examined with MTT assay and it was found that Quercetin loaded alginate sealed Agaricus bisporus derived ß-glucan particles were having lowest IC50. Further ROS generation was found to increase in a dose dependent manner. Apoptosis detection was carried out with Propidium iodide and AO/EtBr staining dye which showed significant death in the cells treated with higher concentration of the particles. Study showed that particles derived from both of the sources were having efficient anticancer activity and showing a dose dependent increase in cell death in PC3 cells upon treatment.