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Fungal Biology and Biotechnology 2020Fungal secondary metabolites are synthesized by complex biosynthetic pathways catalized by enzymes located in different subcellular compartments, thus requiring traffic... (Review)
Review
Fungal secondary metabolites are synthesized by complex biosynthetic pathways catalized by enzymes located in different subcellular compartments, thus requiring traffic of precursors and intermediates between them. The β-lactam antibiotics penicillin and cephalosporin C serve as an excellent model to understand the molecular mechanisms that control the subcellular localization of secondary metabolites biosynthetic enzymes. Optimal functioning of the β-lactam biosynthetic enzymes relies on a sophisticated temporal and spatial organization of the enzymes, the intermediates and the final products. The first and second enzymes of the penicillin pathway, ACV synthetase and IPN synthase, in and are cytosolic. In contrast, the last two enzymes of the penicillin pathway, phenylacetyl-CoA ligase and isopenicillin N acyltransferase, are located in peroxisomes working as a tandem at their optimal pH that coincides with the peroxisomes pH. Two MFS transporters, PenM and PaaT have been found to be involved in the import of the intermediates isopenicillin N and phenylacetic acid, respectively, into peroxisomes. Similar compartmentalization of intermediates occurs in two enzymes isopenicillin N-CoA ligase and isopenicillin N-CoA epimerase, that catalyse the conversion of isopenicillin N in penicillin N, are located in peroxisomes. Two genes encoding MFS transporters, and are located in the early cephalosporin gene cluster. These transporters have been localized in peroxisomes by confocal fluorescence microscopy. A third gene of , , encodes an MFS protein, located in the cell membrane involved in the secretion of cephalosporin C, although -disrupted mutants are still able to export cephalosporin by redundant transporters. The secretion of penicillin from peroxisomes to the extracellular medium is still unclear. Attempts have been made to identify a gene encoding the penicillin secretion protein among the 48 ABC-transporters of . The highly efficient secretion system that exports penicillin against a concentration gradient may involve active penicillin extrusion systems mediated by vesicles that fuse to the cell membrane. However, there is no correlation of pexophagy with penicillin or cephalosporin formation since inactivation of pexophagy leads to increased penicillin or cephalosporin biosynthesis due to preservation of peroxisomes. The penicillin biosynthesis finding shows that in order to increase biosynthesis of novel secondary metabolites it is essential to adequately target enzymes to organelles.
PubMed: 32351700
DOI: 10.1186/s40694-020-00096-y -
Plants (Basel, Switzerland) Dec 2023Plant-endophytic microbes affect plant growth, development, nutrition, and resistance to pathogens. However, how endophytic microbial communities change in different...
Plant-endophytic microbes affect plant growth, development, nutrition, and resistance to pathogens. However, how endophytic microbial communities change in different strawberry plant compartments after pathogen infection has remained elusive. In this study, 16S and internal transcribed spacer rRNA amplicon sequencing were used to systematically investigate changes in the bacterial and fungal diversity and composition in the endophytic compartments (roots, stems, and leaves) of healthy strawberries and strawberries with wilt, respectively. The analysis of the diversity, structure, and composition of the bacterial and fungal communities revealed a strong effect of pathogen invasion on the endophytic communities. The bacterial and fungal community diversity was lower in the -infected endophytic compartments than in the healthy samples. The relative abundance of certain bacterial and fungal genera also changed after wilt infection. The relative abundance of the beneficial bacterial genera , , , , , and , as well as fungal genera , , , and , were higher in the healthy samples than in the wilt samples. The relative abundance of in the infected samples was significantly higher than that in the healthy samples, consistent with the field observations and culture isolation results for strawberry wilt. Our findings provide a theoretical basis for the isolation, identification, and control of strawberry wilt disease.
PubMed: 38140478
DOI: 10.3390/plants12244153 -
Mycobiology 2023The aim of this study was to characterize a new fungal species, , isolated from air samples collected in Wando, South Korea. Phylogenetic analysis based on the internal...
The aim of this study was to characterize a new fungal species, , isolated from air samples collected in Wando, South Korea. Phylogenetic analysis based on the internal transcribed spacer and large subunit regions revealed its unique position within the genus . The isolated strain displayed distinct morphological characteristics, including ellipsoid or bent-ellipsoid conidia formed in clusters on the phialides. These features differentiate the new species from closely related species within the genus. This study describes the morphological and molecular characteristics of and emphasizes its phylogenetic relationships with other spp. The identification of this novel species contributes to our understanding of the diversity and ecological role of .
PubMed: 37711986
DOI: 10.1080/12298093.2023.2242646 -
Heliyon Jan 2020In this study we explored the cultivable fungal diversity in Lake Magadi and their secondary metabolite production. Isolation was done on alkaline media (Potato dextrose...
In this study we explored the cultivable fungal diversity in Lake Magadi and their secondary metabolite production. Isolation was done on alkaline media (Potato dextrose agar, Malt extract agar, Oatmeal agar and Sabouraud dextrose agar). A total of 52 unique isolates were recovered from the lake and were characterized using different techniques. Growth was observed at pH, temperature and salinity ranges of between 6 - 10, 25 °C - 40 °C and 0%-20% respectively. Phylogenetically, the isolates were affiliated to 18 different genera with , and being dominant. A screen for the ability to produce extracellular enzymes showed that different isolates could produce proteases, chitinases, cellulases, amylases, pectinases and lipases. Production of antimicrobial metabolites was noted for isolate 11M affiliated to (99%). Cell free extracts and crude extracts from this isolate had inhibitory effects on , , ., , and fungal plant pathogens strain JME-11 strain EG11-4 CBS 119416 and ). In this study we showed that different cultivation strategies can lead to recovery of more phylotypes from the extreme environments. Growth under different physiological characteristics typical of the soda lake environment (elevated temperature, pH and salts) confirmed the haloalkaliphilic nature of the fungal isolates. The use of suitable antimicrobial production media can also lead to discovery of more phylotypes producing diverse biocatalysts and bioactive metabolites.
PubMed: 31938738
DOI: 10.1016/j.heliyon.2019.e02823 -
Frontiers in Microbiology 2022Endophytic fungi are microorganisms with the ability to colonize plants for the entire or at least a significant part of their life cycle asymptomatically, establishing...
Endophytic fungi are microorganisms with the ability to colonize plants for the entire or at least a significant part of their life cycle asymptomatically, establishing a plant-fungus association. They play an important role in balancing ecosystems, as well as benefiting host through increasing plant growth, and protecting the host plants from abiotic and biotic stresses using various strategies. In the present study, endophytic fungi were isolated from wild and endemic apple cultivars, followed by characterizing their antifungal effect against . To characterize the endophytic fungi, 417 fungal strains were separated from 210 healthy fruit, leaf, and branch samples collected from the north of Iran. Among the purified fungal isolates, 33 fungal genera were identified based on the morphological characteristics, of which 38 species were detected according to the morphological features and molecular data of ITS, , and genomic regions (related to the genus). The results represented that most of the endophytic fungi belonged to Ascomycota (67.8%), 31.4% of isolates were mycelia sterilia, while the others were Basidiomycota (0.48%) and Mucoromycota (0.24%). Additionally, , , and were determined as the dominant genera. The antifungal properties of the identified isolates were evaluated against to determine the release of media-permeable metabolites, Volatile Organic Compounds (VOCs), chitinase, and cellulase as antifungal mechanisms, as well as producing phosphate solubilisation as growth-promoting effect. Based on the results of metabolite and VOC tests, the six isolates of GO13S1, 55S2, 61S2, 7F2, 2S1 and 3 L2 were selected for greenhouse tests. Further, 55S2 and 61S2 could solubilize inorganic phosphate. All isolates except 3 L2 exhibited cellulase activity, while chitinase activity was observed in 2S1, 3 L2, and 61S2. Finally, 55S2 and 2S1 completely controlled the disease on the apple seedling leaves under greenhouse conditions.
PubMed: 36419433
DOI: 10.3389/fmicb.2022.1024001 -
Frontiers in Veterinary Science 2022With diversification of yak breeding, it is important to understand the effects of feed type on the rumen, especially microbiota and metabolites. Due to the unique...
With diversification of yak breeding, it is important to understand the effects of feed type on the rumen, especially microbiota and metabolites. Due to the unique characteristics of yak, research on rumen microbes and metabolites is limited. In this study, the effects of two diet types on rumen eukaryotic microflora and metabolites were evaluated using the Illumina MiSeq platform and liquid chromatography-mass spectrometry (LC-MS). All identified protozoa belonged to . At the genus level, the relative abundance of and were significantly ( < 0.05) higher in the roughage group than that of concentrate group, while the concentrate group harbored more . , and were the main fungal phyla, and the , and genera were significantly ( < 0.05) more abundant in the roughage group than the concentrate group, while the concentrate group harbored more , and ( < 0.05). Metabolomics analysis showed that feed type significantly affected the metabolites of rumen protein digestion and absorption (L-proline, L-phenylalanine, L-tryosine, L-leucine, L-tryptophan, and β-alanine), purine metabolism (hypoxanthine, xanthine, guanine, guanosine, adenosine, and adenine), and other metabolic pathway. Correlation analysis revealed extensive associations between differential microorganisms and important metabolites. The results provide a basis for comprehensively understanding the effects of feed types on rumen microorganisms and metabolites of yaks. The findings also provide a reference and new directions for future research.
PubMed: 36619966
DOI: 10.3389/fvets.2022.1027967 -
Indian Journal of Ophthalmology Oct 2022To study the risk factors, clinical presentation, management options, and outcomes in cases of culture-proven Acremonium keratitis.
PURPOSE
To study the risk factors, clinical presentation, management options, and outcomes in cases of culture-proven Acremonium keratitis.
METHODS
Medical and microbiology records of culture-proven Acremonium keratitis from Jan 2007 to Dec 2019 at a tertiary eye care center were reviewed. Details of clinical findings on each visit and operating notes were reviewed from the medical records. All cases were subjected to corneal scraping at the first visit for microbiological investigation consisting of direct smear examination and culture. Topical natamycin 5% was the mainstay of medical treatment. Surgical treatment was considered for nonresponding patients.
RESULTS
During the 13-year study period, 65 cases of culture-proven Acremonium keratitis were identified out of 1605 cases of fungal keratitis. Trauma was the most common predisposing factor in 32 cases (49.2%). The average area of the corneal stromal infiltrate was 24.8 mm at the initial presentation. Hypopyon at the time of presentation was evident in 28 (43.1%) cases. Staphylococcus spp. was the most common (n = 22, 33.8%) organism coexistent with Acremonium. Direct microscopy of corneal scraping was positive for fungal filaments in 57/65 (87.6%) cases. Medical management alone was given in 44 patients (67.6%). Age (>50 years) and treatment delay (>15 days) were found to be independent risk factors for the poor final visual outcome (VA <20/60).
CONCLUSION
When treated early, Acremonium keratitis responds well to medical therapy with currently available topical antifungals. However, advanced and nonresponding cases require surgical intervention for resolution of the infection.
Topics: Acremonium; Antifungal Agents; Corneal Diseases; Eye Infections, Fungal; Humans; Keratitis; Middle Aged; Natamycin; Retrospective Studies; Risk Factors
PubMed: 36190039
DOI: 10.4103/ijo.IJO_659_22 -
ACS Omega Sep 2023The purpose of this study was to compare and explore the potential of two distinct lipases at industrial levels after their production using wheat bran substrate in...
The purpose of this study was to compare and explore the potential of two distinct lipases at industrial levels after their production using wheat bran substrate in solid-state fermentation. Lipases from () and () were characterized to assess their compatibility and suitability for use in laundry detergents. The effects of pH, temperature, metal ions, inhibitors, organic solvents, and various commercially available detergents on these lipases were studied in order to compare their activity and stability profiles and check their stain removal ability. Both lipases remained stable across the wide pH (7-10) and temperature (30-50 °C) ranges. lipase exhibited optimum activity (51.66 U/mL) at pH 7.0 and 37 °C, while lipase showed optimum activity (52.12 U/mL) at pH 8.0 and 40 °C. The addition of Ca and Mg ions enhanced their activities, while sodium dodecyl sulfate (SDS) and ethylenediamine tetraacetic acid (EDTA) reduced their activities. Lipase from both strains showed tolerance to various organic solvents and considerable stability and compatibility with commercially available laundry detergents (>50%); however, lipase performed slightly better. Characterization of these crude lipases showed nearly 60% relative activity after incubation for 2 h in various detergents, thus suggesting their potential to be employed in the formulation of laundry detergents with easy and efficient enzyme production. The production of thermostable and alkaline lipases from both strains makes them an attractive option for economic gain by lowering the amount of detergent to be used, thus reducing the chemical burden on the environment.
PubMed: 37720795
DOI: 10.1021/acsomega.3c03644 -
Planta Medica Oct 2023Fungi-derived polyketide-terpenoid hybrids are important meroterpenoid natural products that possess diverse structure scaffolds with a broad spectrum of bioactivities.... (Review)
Review
Fungi-derived polyketide-terpenoid hybrids are important meroterpenoid natural products that possess diverse structure scaffolds with a broad spectrum of bioactivities. Herein, we focus on an ever-increasing group of meroterpenoids, orsellinic acid-sesquiterpene hybrids comprised of biosynthetic start unit orsellinic acid coupling to a farnesyl group or/and its modified cyclic products. The review entails the search of China National Knowledge Infrastructure (CNKI), Web of Science, Science Direct, Google Scholar, and PubMed databases up to June 2022. The key terms include "orsellinic acid", "sesquiterpene", "ascochlorin", "ascofuranone", and "", which are combined with the structures of "ascochlorin" and "ascofuranone" drawn by the Reaxys and Scifinder databases. In our search, these orsellinic acid-sesquiterpene hybrids are mainly produced by filamentous fungi. Ascochlorin was the first compound reported in 1968 and isolated from filamentous fungus (synonym: ); to date, 71 molecules are discovered from various filamentous fungi inhabiting in a variety of ecological niches. As typical representatives of the hybrid molecules, the biosynthetic pathway of ascofuranone and ascochlorin are discussed. The group of meroterpenoid hybrids exhibits a broad arrange of bioactivities, as highlighted by targeting hDHODH (human dihydroorotate dehydrogenase) inhibition, antitrypanosomal, and antimicrobial activities. This review summarizes the findings related to the structures, fungal sources, bioactivities, and their biosynthesis from 1968 to June 2022.
Topics: Humans; Sesquiterpenes; Ascomycota; Terpenes
PubMed: 37225133
DOI: 10.1055/a-2099-4932 -
Persoonia Dec 2020Novel species of fungi described in this study include those from various countries as follows: , on soil, on leaves of on leaves of on leaves of sp., on soil,...
Novel species of fungi described in this study include those from various countries as follows: , on soil, on leaves of on leaves of on leaves of sp., on soil, (incl. gen. nov.) on leaves of , from stem tissue of , on soil, (incl. gen. nov.) and on leaves of on leaves of , from pond water, Serendipita whamiae as endophyte from roots of , (incl. gen. nov.) on soil. , on soil. , from the gut of found on a sp. , among leaf litter of , from house dust. , on soil, from rhizosphere of , on leaves of , on fallen branch of . , on soil, from dead wood of , on litter of deciduous wood, on forest litter. , (Martinique) on leaves of , from bore dust of infesting floorboards. , on dead corticated branch. , on soil. , among leaf litter of , on infected leaves of sp., (incl. gen. nov.) on wood of , from compost. , on plant litter, and (incl. gen. nov.) on leaves and flowers of (incl. gen. nov.) on leaves of on dung of , from soil on forest floor. , from . , on leaves of and (incl. gen. nov.) on leaves of , on leaves of , on leaves of , from inner fruit tissue of sp., on leaves of , on leaves of , on leaf spots of , on leaves of , on stems of , from roots of sp., and on leaves of , on leaves of . , on cow dung, from deciduous woodlands. , on needles of , from stream sediment, on soil under , on sp. , on fruits of from bat guano, on culms of , on scale insect, (incl. gen. nov.) on stem cankers of , from cave sediment. , on leaf litter, on soil in montane evergreen broadleaf forest. Morphological and culture characteristics are supported by DNA barcodes.
PubMed: 34456379
DOI: 10.3767/persoonia.2020.45.10