Mold Research Articles

Trichoderma spp. isolates stimulate rice seedling growth of Sertani 13 variety

Trichoderma has become one of the most studied filamentous fungi to be used as a greener and more sustainable solution for improving the production and growth of numerous crops, due to its capability to form symbiotic associations with plants. This study aimed to evaluate the effect of Trichoderma isolates obtained from the rhizosphere of organic rice fields in Sukabumi, Indonesia, in enhancing rice germination and seedling growth. A laboratory experiment used a completely randomized design consisting of seed treatments of 21 Trichoderma isolates (T1-T21) and a control treatment without Trichoderma (C). The inoculation was employed to elucidate any potential effects of Trichoderma isolates. Results showed that five isolates, i.e., T5, T7, T9, T10, and T14 stimulated the highest seedling vigor index, root and shoot length, and fresh weight and dry weight. These findings exhibited the potential of these five isolates as plant growth-promoting fungi to improve rice seedling growth and contribute to our understanding of the role of symbiotic fungi in sustainable rice crop production. Keywords: plant growth promoting fungi; seed treatment; plant-microbe interactions, symbiotic fungi

Application of Biosensors for the Detection of Mycotoxins for the Improvement of Food Safety.

Mycotoxins, secondary metabolites synthesized by various filamentous fungi genera such as Aspergillus, Penicillium, Fusarium, Claviceps, and Alternaria, are potent toxic compounds. Their production is contingent upon specific environmental conditions during fungal growth. Arising as byproducts of fungal metabolic processes, mycotoxins exhibit significant toxicity, posing risks of acute or chronic health complications. Recognized as highly hazardous food contaminants, mycotoxins present a pervasive threat throughout the agricultural and food processing continuum, from plant cultivation to post-harvest stages. The imperative to adhere to principles of good agricultural and industrial practice is underscored to mitigate the risk of mycotoxin contamination in food production. In the domain of food safety, the rapid and efficient detection of mycotoxins holds paramount significance. This paper delineates conventional and commercial methodologies for mycotoxin detection in ensuring food safety, encompassing techniques like liquid chromatography, immunoassays, and test strips, with a significant emphasis on the role of electrochemiluminescence (ECL) biosensors, which are known for their high sensitivity and specificity. These are categorized into antibody-, and aptamer-based, as well as molecular imprinting methods. This paper examines the latest advancements in biosensors for mycotoxin testing, with a particular focus on their amplification strategies and operating mechanisms.

Histone H3 N-Terminal Lysine Acetylation Governs Fungal Growth, Conidiation, and Pathogenicity through Regulating Gene Expression in Fusarium pseudograminearum.

The acetylation of histone lysine residues regulates multiple life processes, including growth, conidiation, and pathogenicity in filamentous pathogenic fungi. However, the specific function of each lysine residue at the N-terminus of histone H3 in phytopathogenic fungi remains unclear. In this study, we mutated the N-terminal lysine residues of histone H3 in Fusarium pseudograminearum, the main causal agent of Fusarium crown rot of wheat in China, which also produces deoxynivalenol (DON) toxins harmful to humans and animals. Our findings reveal that all the FpH3K9R, FpH3K14R, FpH3K18R, and FpH3K23R mutants are vital for vegetative growth and conidiation. Additionally, FpH3K14 regulates the pathogen's sensitivity to various stresses and fungicides. Despite the slowed growth of the FpH3K9R and FpH3K23R mutants, their pathogenicity towards wheat stems and heads remains unchanged. However, the FpH3K9R mutant produces more DON. Furthermore, the FpH3K14R and FpH3K18R mutants exhibit significantly reduced virulence, with the FpH3K18R mutant producing minimal DON. In the FpH3K9R, FpH3K14R, FpH3K18R, and FpH3K23R mutants, there are 1863, 1400, 1688, and 1806 downregulated genes, respectively, compared to the wild type. These downregulated genes include many that are crucial for growth, conidiation, pathogenicity, and DON production, as well as some essential genes. Gene ontology (GO) enrichment analysis indicates that genes downregulated in the FpH3K14R and FpH3K18R mutants are enriched for ribosome biogenesis, rRNA processing, and rRNA metabolic process. This suggests that the translation machinery is abnormal in the FpH3K14R and FpH3K18R mutants. Overall, our findings suggest that H3 N-terminal lysine residues are involved in regulating the expression of genes with important functions and are critical for fungal development and pathogenicity.

Exploring the Subcellular Localization of Monascus Pigments Biosynthases: Preliminary Unraveling of the Compartmentalization Mechanism.

Monascus pigments (MPs), a class of secondary metabolites produced by Monascus spp., can be classified into yellow, orange, and red MPs according to their differences in the wavelength of the maximum absorption. However, the biosynthetic sequence and cellular biosynthesis mechanism of different MPs components are still not yet completely clear in Monascus spp. In this study, the subcellular localization of five MPs synthases was investigated using fluorescent protein fusion expression. The results revealed that the proteins encoded by the MPs biosynthetic gene cluster were compartmentalized in various subcellular locations, including the mitochondrial polyketide synthase MrPigA, cytosolic enzymes consisting of the ketoreductase MrPigC, the oxidoreductase MrPigE, and the monooxygenase MrPigN, and the cell-wall-bound oxidoreductase MrPigF. Moreover, the correct localization of MrPigF to the cell wall was crucial for the synthesis of orange MPs. Lastly, we discussed the compartmentalized biosynthetic pathway of MPs. This study will not only be helpful in clarifying the biosynthetic sequence and biosynthesis mechanism of different MPs but also provides new insights into the cellular biosynthesis of secondary metabolites in filamentous fungi.

Mrvam7, a conserved SNARE gene involved in vacuolar fusion, is required for development and secondary metabolism in Monascus ruber M7

Vam7 (vacuolar morphogenesis 7), a Qc-soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) that mediates vacuolar fusion, is involved in vacuolar morphogenesis, vegetative growth, sexual and asexual reproduction, and compartmentalized biosynthesis of secondary metabolites in various filamentous fungi. In this study, the homolog of vam7 gene, mrvam7, in Monascus ruber M7 was functionally characterized through gene modification and transcriptome analysis. The results showed that the mrvam7 complementation and overexpression strains exhibited phenotypic similarities to M. ruber M7, whereas the mrvam7 null strain exhibited fragmented vacuoles, slowed growth and diminished sexual and asexual sporulation. Furthermore, the mrvam7 knockout strain displayed a notable increase in citrinin production alongside a significant decrease in Monascus pigments production. Transcriptome data revealed that the deletion of mrvam7 altered the expression levels of several genes involved in sexual and asexual reproduction, carbon and nitrogen source utilization, and secondary metabolites biosynthetic gene clusters. Collectively, these findings underscore the critical role of mrvam7-mediated vacuolar fusion in growth, development, and the compartmentalized biosynthesis and distribution of secondary metabolites in M ruber M7. This study provides novel insights into the mechanisms underlying of compartmentalized secondary metabolites biosynthesis in Monascus species.

The Identification of the Mitochondrial DNA Polymerase γ (Mip1) of the Entomopathogenic Fungus Metarhizium brunneum.

Replication of the mitochondrial (mt) genome in filamentous fungi is under-studied, and knowledge is based mainly on data from yeasts and higher eukaryotes. In this study, the mitochondrial DNA polymerase γ (Mip1) of the entomopathogenic fungus Metarhizium brunneum is characterized and analyzed with disruption experiments and its in silico interactions with key proteins implicated in mt gene transcription, i.e., mt RNA polymerase Rpo41 and mt transcription factor Mtf1. Disruption of mip1 gene and its partial expression influences cell growth, morphology, germination and stress tolerance. A putative in silico model of Mip1-Rpo41-Mtf1, which is known to be needed for the initiation of replication, was proposed and helped to identify potential amino acid residues of Mip1 that interact with the Rpo41-Mtf1 complex. Moreover, the reduced expression of mip1 indicates that Mip1 is not required for efficient transcription but only for replication. Functional differences between the M. brunneum Mip1 and its counterparts from Saccharomyces cerevisiae and higher eukaryotes are discussed.

Evaluation of CHROMagar™ B. cepacia agar for the detection of Burkholderia cepacia complex species from sputum samples of patients with cystic fibrosis

IntroductionBurkholderia cepacia complex (BCC) are non-fermenting Gram-negative bacteria that can chronically colonize the lungs of people with cystic fibrosis (pwCF), causing a severe and progressive respiratory failure, post-transplant complications and epidemic outbreaks. Therefore, rapid and accurate identification of these bacteria is relevant for pwCF, in order to facilitate early eradication and prevent chronic colonization. However, BCCs are often quite difficult to detect on culture media as they have a slow growth rate and can be hidden by other fast-growing microorganisms, including Pseudomonas aeruginosa and filamentous fungi.Material and methodsWe evaluated the sensitivity of CHROMagar™ B. cepacia agar using 11 isolates from a well-characterized BCC collection, using BCA agar (Oxoid, UK) as a gold standard. We also studied 180 clinical sputum samples to calculate positive (PPV) and negative (NPV) predictive values. Furthermore, we used three of the well-characterized BCC isolates to determine the limit of detection (LOD).ResultsEleven isolates grew on CHROMagar™ B. cepacia at 37ºC after 48 h. The NPV and PPV of CHROMagar™ B. cepacia were 100% and 87.5%, respectively. The LOD of CHROMagar™ B. cepacia was around 1 × 103 CFU/ml, requiring a ten-fold dilution lower bacterial load than BCA for BCC detection.ConclusionCHROMagar™ B. cepacia agar proved to have a very good sensitivity and specificity for the detection of clinical BCCs. Moreover, the chromogenic nature of the medium allowed us to clearly differentiate BCC from other Gram-negative species, filamentous fungi and yeasts, thereby facilitating the identification of contaminants.

Loss of a conserved C-terminal region of the Aspergillus fumigatus AtrR transcriptional regulator leads to a gene-specific defect in target gene expression.

Treatment of fungal infections associated with the filamentous fungus Aspergillus fumigatus is becoming more problematic as this organism is developing resistance to the main chemotherapeutic drug at an increasing rate. Azole drugs represent the current standard-of-care in treatment of aspergillosis with this drug class acting by inhibiting a key step in biosynthesis of the fungal sterol ergosterol. Azole compounds block the activity of the lanosterol α-14 demethylase, encoded by the cyp51A gene. A common route of azole resistance involves an increase in transcription of cyp51A. This transcriptional increase requires the function of a Zn2Cys6 DNA-binding domain-containing transcription activator protein called AtrR. AtrR was identified through its action as a positive regulator of expression of an ATP-binding cassette transporter (abcC/cdr1B here called abcG1). Using both deletion and alanine scanning mutagenesis, we demonstrate that a conserved C-terminal domain in A. fumigatus is required for expression of abcG1 but dispensable for cyp51A transcription. This domain is also found in several other fungal pathogen AtrR homologues consistent with a conserved gene-selective function of this protein segment being conserved. Using RNA-seq, we find that this gene-specific transcriptional defect extends to several other membrane transporter-encoding genes including a second ABC transporter locus. Our data reveal that AtrR uses at least two distinct mechanisms to induce gene expression and that normal susceptibility to azole drugs cannot be provided by maintenance of wild-type expression of the ergosterol biosynthetic pathway when ABC transporter expression is reduced.

Phosphatidylcholine levels regulate hyphal elongation and differentiation in the filamentous fungus Aspergillus oryzae

Filamentous fungi are eukaryotic microorganisms that differentiate into diverse cellular forms. Recent research demonstrated that phospholipid homeostasis is crucial for the morphogenesis of filamentous fungi. However, phospholipids involved in the morphological regulation are yet to be systematically analyzed. In this study, we artificially controlled the amount of phosphatidylcholine (PC), a primary membrane lipid in many eukaryotes, in a filamentous fungus Aspergillus oryzae, by deleting the genes involved in PC synthesis or by repressing their expression. Under the condition where only a small amount of PC was synthesized, A. oryzae hardly formed aerial hyphae, the basic structures for asexual development. In contrast, hyphae were formed on the surface or in the interior of agar media (we collectively called substrate hyphae) under the same conditions. Furthermore, we demonstrated that supplying sufficient choline to the media led to the formation of aerial hyphae from the substrate hyphae. We suggested that acyl chains in PC were shorter in the substrate hyphae than in the aerial hyphae by utilizing the strain in which intracellular PC levels were controlled. Our findings suggested that the PC levels regulate hyphal elongation and differentiation processes in A. oryzae and that phospholipid composition varied depending on the hyphal types.

Insight into selenium biofortification and the selenite metabolic mechanism of Monascus ruber M7

Monascus species are functional fermentation fungi with great potential for selenium (Se) supplementation. This study investigated the effects of Se bio-fortification on the growth, morphology, and biosynthesis of Monascus ruber M7. The results demonstrated a significant increase in the yield of orange and red Monascus pigments (MPs) in red yeast rice (RYR) by 38.52% and 36.57%, respectively, under 20 μg/mL of selenite pressure. Meanwhile, the production of citrinin (CIT), a mycotoxin, decreased from 244.47 μg/g to 175.01 μg/g. Transcriptome analysis revealed significant upregulation of twelve genes involved in MPs biosynthesis, specifically MpigE, MpigF, and MpigN, and downregulation of four genes (mrr3, mrr4, mrr7, and mrr8) associated with CIT biosynthesis. Additionally, three genes encoding cysteine synthase cysK (Log2FC = 1.6), methionine synthase metH (Log2FC = 2.2), and methionyl-tRNA synthetase metG (Log2FC = 1.8) in selenocompound metabolism showed significantly upregulated. These findings provide insights into Se biotransformation and metabolism in filamentous fungi.

Fungal and Prokaryotic Communities in Soil Samples of the Aral Sea Dry Bottom in Uzbekistan

Due to the falling water level in the Aral Sea and Muynak Lake, the content of salts dissolved in the water has gradually increased, and toxic elements have been deposited at the lake’s bottom and subsequently washed into the Aral region by the river. Bacteria, archaea and fungi are crucial for the cycling of several important inorganic nutrients in soils. From 15 genera and 31 species of recovered microscopic filamentous fungi, a big group was melanized, of which most of them were also phytopathogenic. The second group consisted of keratinophilic species. Isolated bacteria mainly included members of the genera Arthrobacter, Bacillus, Massilia, Rhodococcus and Nocardiopsis. High-throughput sequencing analysis permitted a better view of the mycobiome and prokaryotic communities (comprising archaea). The cultivation and sequencing approaches were shown to be complementary. The aim of the work was to identify soil microorganisms, including the order Halobacteriales, and to discover the differences in species diversity depending on soil salinity and the presence of PTEs in soil.

Clinical, microbiologic, and treatment outcomes of dematiaceous fungal keratitis - A retrospective study.

Dematiaceous fungi, the third most common causative organism of fungal keratitis, constitute 3.5% to 43.5% of fungal keratitis worldwide. Several studies on filamentous fungi (Aspergillus and Fusarium) are available as opposed to that on dematiaceous fungal keratitis. This study aims to describe the profile of dematiaceous fungal keratitis in South India. This institutional cohort study on culture-proven dematiaceous fungal keratitis was performed in a single ophthalmology referral center in South India for a 6-year period. Records were analyzed for demographic, clinical, microbiological, and treatment outcomes for 3 months from the date of presentation. This study comprised 312 cases involving dematiaceous fungal keratitis (DFK). During the study period, DFK accounted for 10% of microbial keratitis and 24.6% of fungal keratitis cases. The mean (standard deviation) age was 54 (14) years. Males were commonly affected (73.4%). Keratitis was ≤1/3rd depth in 47.8% of cases. Fifty-four cases (17.3%) demonstrated surface pigmentation, and 69 cases (22.1%) had endothelial plaque. Curvularia spp. (99 eyes, 31.7%) was the most common fungal isolate among the speciated fungi. Topical medications resulted in the healing of 63.5% of cases. A total of 193 cases (79%) healed, and 49 cases had to undergo therapeutic penetrating keratoplasty (TPK). Early TPK was performed for 20 cases (40.8%). Seventeen eyes (34.6%) maintained clear grafts at the end of 3 months. In this extensive study on DFK, we report a high incidence of this group of fungal keratitis. We found an excellent healing rate in our cohort of patients.

Molecular Identification of Ascomycetes from American Cranberry (Vaccinium macrocarpon Aiton) Grown in Plantation in Poland

The American cranberry is a perennial North American fruit plant that is grown successfully on commercial plantations in Poland. The purpose of this study was to recognize filamentous fungi that colonize roots, leaves, and fruits without visible disease symptoms. Pure fungal cultures were isolated from disinfected plant fragments in agar media and identified by sequencing common taxonomic DNA markers such as the ITS region, the TEF-1α, or RPB2 genes. Of the 141 isolates studied, 59% were identified as closely related to soil saprotrophs. They were classified primarily as showing the greatest similarity to type strains of Trichoderma amoenum, Trichoderma dorothopsis, Paraphaeosphaeria sporulosa, and Penicillium murcianum. Additionally, isolates that are most similar to strains of Penicillium crustosum, Aspergillus flavus, and Aspergillus versicolor that produced mycotoxins were detected. The fungi identified as closest to Alternaria geophila, Alternaria senecionicola, Paraphoma radicina, Pestalotiopsis unicolor, Pestalotiopsis scoparia, and Neopestalotiopsis spp., whose hosts are plants other than American cranberry, represented 33.81% of the isolates tested. Only 7.2% of the isolates corresponded to the species of Physalospora vaccinia, Diaporthe vaccinii, and Diaporthe eres, known cranberry pathogens. The results of this study can be used to identify latent plant infection and potential disease risks.

MYCOLOGICAL ANALYSIS OF CYSTIC CONTENT IN PATIENTS WITH POLYMICROCYSTIC CHANGES OF THE MAXILLARY SINUS MUCOSA

The prevalence of mycotic infections of the paranasal sinuses is constantly increasing worldwide. Pathogens can enter the sinuses through the respiratory tract that leads to the colonization of microorganisms in both the lungs and paranasal sinuses as part of the normal microflora. The presence of filamentous fungi in the maxillary sinus may result from endodontic treatment of molars directly adjacent to the sinus, increasing the risk of fungal foci development. Fungal paranasal sinusitis manifests in invasive or non-invasive forms. While mycological culture remains the traditional gold standard for mycosis diagnosis, its sensitivity is reportedly low. Paranasal sinus cysts comprise 4-8% of general ENT pathologies and approximately 4-16% of chronic paranasal sinus diseases, with a predominant presence in the maxillary sinus. Factors that contribute to the development of sinusitis and create favorable conditions for fungal spore adhesion and growth include impaired ventilation and transport function of the sinus mucosa, inadequate use of broad-spectrum antibacterial drugs and steroid therapy, as well as household factors. Recently, there has been an increase in the number of cases of multiple small cysts in maxillary sinuses. Clinical manifestations range from asymptomatic incidental findings to varying degrees of discomfort and/or pain localized in the maxillary sinus area. The aim of this study is to identify the involvement of a fungal agent and to develop a set of therapeutic and prophylactic measures for polymicrocystic changes in the mucous membrane of the maxillary sinuses. The study enrolled 37 patients aged 18 to 65 years. Atypical cystic content was collected and cultured in Sabouraud's nutrient broth and Amies transport medium at 35-37°C for 5-7 days, with final measurements on day 21. Treatment involved a 14-day regimen of itraconazole (100 mg once daily) alongside topical miramistin (0.01% solution, 2 ml) sinus injections. The findings obtained demonstrate the following: positive fungal growth was observed in 26 cases (70.3%), predominantly Penicillium (48.6%) and Aspergillus (21.6%). Absence of growth was noted in 11 cases (29.7%). Follow-up examinations in 6 months and in a year revealed no crusts in the nasal cavity, moderate mucous discharge in the sinuses, and no polymicrocystic changes. Conclusion. The analysis has demonstrated the involvement of fungal flora in the development and recurrence of cystic changes in the maxillary sinus mucosa, advocating for mycological examination alongside bacteriological analysis. Itraconazole for systemic therapy and miramistin for topical therapy demonstrate efficacy in treatment and recurrence prevention.

Fermented Products Enriched with Polyunsaturated Fatty Acids in Broiler Chicken Nutrition and Fat Quality of Produced Meat

Broiler chicken meat is the preferred meat among the human population. Broiler meat contains high-quality protein and a low-fat content, alongside a desirable fatty acid profile. A frequent problem in human nutrition is an insufficient PUFA intake in the diet. One possible strategy to increase the dietary intake of polyunsaturated fatty acids (PUFA) in humans is to produce, and thereby enrich, broiler chicken meat with sufficient amounts of essential PUFA. A method to increase the proportion of essential fatty acids in chicken meat is by changing the fatty acid composition of the feed. Feed production via solid-state fermentation using lower filamentous fungi can be used to prepare valuable feed from cereal by-products enriched with important PUFA and pigments and can thus be included as a suitable feed ingredient in the diet of chickens. From previously published studies, it can be concluded that the application of 3–10% of the prepared fermented products to the diet of broiler chickens increased the proportion of essential fatty acids in the fat of the chicken meat and had a beneficial effect on the growth parameters of chickens.

Reconstitution of the Early Stage of Chetomin Biosynthesis in Aspergillus fumigatus Leads to the Production of Epipolythiodioxopiperazines.

Using CRISPR-Cas9 technology and a microhomology-mediated end-joining repair system, we substituted genes of the gliotoxin pathway in Aspergillus fumigatus with genes responsible for chetomin biosynthesis from Chaetomium cochliodes, leading to the production of three new epipolythiodioxopiperazines (ETPs). This work represents the first successful endeavor to produce ETPs in a non-native host. Additionally, the simultaneous disruption of five genes in a single transformation marks the most extensive gene knockout event in filamentous fungi to date.

Symbiotic bacteria and fungi proliferate in diapause and may enhance overwintering survival in a solitary bee.

Host-microbe interactions underlie the development and fitness of many macroorganisms, including bees. Whereas many social bees benefit from vertically transmitted gut bacteria, current data suggests that solitary bees, which comprise the vast majority of species diversity within bees, lack a highly specialized gut microbiome. Here, we examine the composition and abundance of bacteria and fungi throughout the complete life cycle of the ground-nesting solitary bee Anthophora bomboides standfordiana. In contrast to expectations, immature bee stages maintain a distinct core microbiome consisting of Actinobacterial genera (Streptomyces, Nocardiodes) and the fungus Moniliella spathulata. Dormant (diapausing) larval bees hosted the most abundant and distinctive bacteria and fungi, attaining 33 and 52 times their initial copy number, respectively. We tested two adaptive hypotheses regarding microbial functions for diapausing bees. First, using isolated bacteria and fungi, we found that Streptomyces from brood cells inhibited the growth of multiple pathogenic filamentous fungi, suggesting a role in pathogen protection during overwintering, when bees face high pathogen pressure. Second, sugar alcohol composition changed in tandem with major changes in fungal abundance, suggesting links with bee cold tolerance or overwintering biology. We find that A. bomboides hosts a conserved core microbiome that may provide key fitness advantages through larval development and diapause, which raises the question of how this microbiome is maintained and faithfully transmitted between generations. Our results suggest that focus on microbiomes of mature or active insect developmental stages may overlook stage-specific symbionts and microbial fitness contributions during host dormancy.

Successful cultivation of edible fungi on textile waste offers a new avenue for bioremediation and potential food production

Textile waste contains both natural fibres such as cotton and bamboo viscose, and synthetic fibres such as elastane and polyester. As a complex mixture, textiles present a challenging pollution issue as breakdown in landfill results in microplastics entering water and soil environments, and incineration results in particulate air pollution. Here the use of edible fungi as bioremediation agents of waste textiles is described for the first time. Three species of filamentous fungi were shown to colonise and grow on mixed fibre textile waste (underpants made from 28% cotton: 68% bamboo viscose: 4% elastane). All three fungi were able to metabolise the common textile dye Reactive Black 5 to some extent. The metabolome was captured to elucidate the dye remediation pathway utilized and to characterise the volatiles released during bioremediation with a view to assessing the safety profile of this process for future industrial applications. The results suggest that edible fungi may be cultivated on textiles, and that some interesting and useful compounds may be produced in the process. This has great biotechnological potential. No mushrooms were produced in this study, suggesting that further work will be needed to optimise conditions for crop production from waste textiles.

Bioactive Components Analysis and Pharmacological Properties of Extracts and Metabolites of Lichen Umbilicaria crustulosa

Lichens, a diverse group of organisms, have a unique structure consisting of fungal filaments and photosynthetic partner cells. This research conducted a comprehensive chemical analysis and evaluation of the anti-inflammatory and antioxidant properties of methanolic and acetone extracts from Umbilicaria crustulosa lichen, along with its isolated metabolites. The process involved separating atranorin and chloratranorin fractions, physodic acid, and gyrophoric acid. Secondary metabolites were identified using chromatographic and spectroscopic data. The total polyphenols content was determined spectrophotometrically. This study examined the antioxidant activity of extracts of the lichen U. crustulosa and the isolated fractions using three methods: DPPH scavenging activity, ABTS scavenging activity, and reducing power. This study also evaluated the acute oral toxicity and the anti-inflammatory activity of the extracts in Wistar albino rats. A higher content of the total phenolic compounds was found in the acetone extract, but antioxidant and anti-inflammatory activities were more prominent in the methanolic extract. The isolated atranorin and chloratranorin fractions and compound physodic acid showed the highest antioxidant activity. No toxic effects were noted in the acute oral toxicity study. This study highlights the potential of the investigated lichen as a valuable source of novel biological agents.

Antimicrobial Properties of Flavonoid Derivatives with Bromine, Chlorine, and Nitro Group Obtained by Chemical Synthesis and Biotransformation Studies.

The search for new substances of natural origin, such as flavonoids, is necessary in the fight against the growing number of diseases and bacterial resistance to antibiotics. In our research, we wanted to check the influence of flavonoids with chlorine or bromine atoms and a nitro group on pathogenic and probiotic bacteria. We synthesized flavonoids using Claisen-Schmidt condensation and its modifications, and through biotransformation via entomopathogenic filamentous fungi, we obtained their glycoside derivatives. Biotransformation yielded two new flavonoid glycosides: 8-amino-6-chloroflavone 4'-O-β-D-(4″-O-methyl)-glucopyranoside and 6-bromo-8-nitroflavone 4'-O-β-D-(4″-O-methyl)-glucopyranoside. Subsequently, we checked the antimicrobial properties of the aforementioned aglycon flavonoid compounds against pathogenic and probiotic bacteria and yeast. Our studies revealed that flavones have superior inhibitory effects compared to chalcones and flavanones. Notably, 6-chloro-8-nitroflavone showed potent inhibitory activity against pathogenic bacteria. Conversely, flavanones 6-chloro-8-nitroflavanone and 6-bromo-8-nitroflavanone stimulated the growth of probiotic bacteria (Lactobacillus acidophilus and Pediococcus pentosaceus). Our research has shown that the presence of chlorine, bromine, and nitro groups has a significant effect on their antimicrobial properties.