Two New Triterpenes from Basidiomata of the Medicinal and Edible Mushroom, Laetiporus sulphureus

In the search for novel anti-infectives from natural sources, fungi, in particular basidiomycetes, have proven to still harbor so much potential in terms of secondary metabolites diversity. There have been numerous reports on isolating numerous secondary metabolites from genus Laetiporus. This study reports on two new triterpenoids, laetiporins C and D, and four known triterpenes from the fruiting body of L. sulphureus. The structures of the isolated compounds were elucidated based on their 1D and 2D nuclear magnetic resonance (NMR) spectroscopic data in combination with high-resolution electrospray mass spectrometric (HR-ESIMS) data. Laetiporin C exhibited weak antifungal activity against Mucor hiemalis. Furthermore, the compounds showed weak antiproliferative activity against the mouse fibroblast L929 and human cancer cell lines, including KB-3-1, A431, MCF-7, PC-3 and A549.

Characterization of Four Novel dsRNA Viruses Isolated from Mucor hiemalis Strains

We previously screened the total nucleic acid extracts of 123 Mucor strains for the presence of dsRNA molecules without further molecular analyses. Here, we characterized five novel dsRNA genomes isolated from four different Mucor hiemalis strains with next-generation sequencing (NGS), namely Mucor hiemalis virus 1a (MhV1a) from WRL CN(M) 122; Mucor hiemalis virus 1b (MhV1b) from NRRL 3624; Mucor hiemalis virus 2 (MhV2) from NRRL 3616; and Mucor hiemalis virus 3 (MhV3) and Mucor hiemalis virus (MhV4) from NRRL 3617 strains. Genomes contain two open reading frames (ORF), which encode the coat protein (CP) and the RNA dependent RNA polymerase (RdRp), respectively. In MhV1a and MhV1b, it is predicted to be translated as a fusion protein via -1 ribosomal frameshift, while in MhV4 via a rare +1 (or−2) ribosomal frameshift. In MhV2 and MhV3, the presence of specific UAAUG pentanucleotide motif points to the fact for coupled translation termination and reinitialization. MhV1a, MhV2, and MhV3 are part of the clade representing the genus Victorivirus, while MhV4 is seated in Totivirus genus clade. The detected VLPs in Mucor strains were from 33 to 36 nm in diameter. Hybridization analysis revealed that the dsRNA molecules of MhV1a-MhV4 hybridized to the corresponding molecules.

Microbial Conjugation Studies of Licochalcones and Xanthohumol

Microbial conjugation studies of licochalcones (1–4) and xanthohumol (5) were performed by using the fungi Mucor hiemalis and Absidia coerulea. As a result, one new glucosylated metabolite was produced by M. hiemalis whereas four new and three known sulfated metabolites were obtained by transformation with A. coerulea. Chemical structures of all the metabolites were elucidated on the basis of 1D-, 2D-NMR and mass spectroscopic data analyses. These results could contribute to a better understanding of the metabolic fates of licochalcones and xanthohumol in mammalian systems. Although licochalcone A 4′-sulfate (7) showed less cytotoxic activity against human cancer cell lines compared to its substrate licochalcone A, its activity was fairly retained with the IC50 values in the range of 27.35–43.07 μM.

Five Tetramic Acid Derivatives Isolated from the Iranian Fungus Colpoma quercinum CCTU A372

Submerged mycelial cultures of the ascomycete Colpoma quercinum CCTU A372 were found to produce five previously undescribed tetramic acids, for which we propose the trivial names colposetins A–C (1–3) and colpomenoic acids A and B (4 and 5), along with the known compounds penicillide (6) and monodictyphenone (7). The planar structures of 1–5 were determined by high-resolution electrospray ionization mass spectrometry (HR-ESIMS) and extensive 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. Their absolute configurations were determined by the combination of electronic circular dischroism (ECD) analysis, J-based configurational analysis, and a rotating-frame Overhauser effect spectroscopy (ROESY) experiment. Colposetin B displayed weak antimicrobial activity against Bacillus subtilis and Mucor hiemalis (MIC 67 µg/mL).

Synthesis of Novel Benzylic 1,2,3-triazole-4-carboxamides and their in vitro Activity Against Clinically Common Fungal Species

A library of novel benzylic 1,2,3-triazole-4-carboxamides (3a-m) were obtained with acceptable yields via a one-pot procedure. The series of compounds was screened for fungicidal activity and evaluated in vitro against four filamentous fungi and four Candida species. The former consisted of Aspergillus fumigatus, Trichosporon cutaneum, Rhizopus oryzae and Mucor hiemalis, and the latter C. krusei, C. albicans, C. utilis and C. glabrata. According to the in vitro assays, 3d and 3e were the most efficient fungicidal agents (of all the test compounds) against R. oryzae, even better than the reference drug (itraconazole). Thus, 3d and 3e represent important scaffolds that can be modified to increase antifungal activity. Additionally, they are candidates for complementary studies on the inhibition of clinical infections produced by Rhizopus spp. strains. Resumen. Se obtuvo una librería de nuevos bencil 1,2,3-triazoles-4-carboxamidas (3a-m) con rendimientos aceptables mediante un procedimiento one-pot. La serie de compuestos se seleccionó para determinar la actividad fungicida llevando a cabo una evaluación in vitro contra cuatro hongos filamentosos y cuatro especies de Candida. Los primeros consistieron en Aspergillus fumigatus, Trichosporon cutaneum, Rhizopus oryzae y Mucor hiemalis, mientras que para las segundas especies, esta fueron C. krusei, C. albicans, C. utilis y C. glabrata. Según los ensayos in vitro, 3d y 3e fueron los agentes fungicidas más eficaces (de todos los compuestos de prueba) contra R. oryzae, incluso mejores que el fármaco de referencia (itraconazol). Por tanto, 3d y 3e representan importantes núcleos que podrían modificarse para aumentar la actividad antifúngica, siendo excelentes candidatos para estudios complementarios sobre la inhibición de infecciones clínicas producidas por Rhizopus spp.

Microbial Transformation of Flavonoids in Cultures of Mucor hiemalis

Flavonoids are plant secondary metabolites that are well known for their health-promoting properties as nutraceuticals in diets. Bioavailability and biological activities of flavonoids vary among the individual subclasses with different patterns of substitution, inclusive of glycosylation, to their basic structures. Many flavonoids exist as glycosides in plants. This study investigated the possibility of glycosylation of flavonoids through biotransformation using filamentous fungi as whole-cell biocatalysts. Microbial transformations of ten flavonoids (four flavones, four flavonols, a flavanone, and an aurone) were performed in cultures of Mucor hiemalis KCTC 26779. As a result, a flavonoid glycoside was obtained which has not been described previously. The chemical structure of this product was elucidated as 6,2′-dimethoxyflavonol-3- O-β-d-glucopyranoside by analyzing 1-dimensional and 2-dimensional-nuclear magnetic resonance spectral and high-resolution electrospray ionization mass spectral data. This compound could be useful for further biological and bioavailability studies, as well as expanding the library of flavonoid derivatives.

Microbial Glycosylation of Phenanthrene and Bibenzyls by Mucor hiemalis

Microbial transformation of denthyrsinin (1), gigantol (2), and batatasin III (3), the major constituents of Dendrobium species (Orchidaceae), was performed using the filamentous fungus Mucor hiemalis KCTC 26779. Three glycosylated metabolites were obtained in the biotransformation of 1-3, and their structures were identified as denthyrsinin-6- O-β-d-glucoside (4), gigantol-5- O-β-d-glucoside (5), and batatasin III-3- O-β-d-glucoside (6) by analyzing 1-dimensional and 2-dimensional-nuclear magnetic resonance spectra, as well as high-resolution electrospray ionization mass spectral data. Among them, metabolite 4 has not been previously reported. Mucor hiemalis was revealed to catalyze enzymatically glucosylation of the hydroxyl group of phenanthrenes and bibenzyls. This research provides an efficient approach for the glycosylation of phenanthrenes and bibenzyls and can expand the library of available phenanthrene and bibenzyl derivatives for further biological evaluations.

Monitoring of Soils Mycobiota of the Yaroslavl Region Agrocoenosis with Different Methods of Сultivation and Application of Fertilizers

Приведены результаты мониторинга состояния микобиоты почвы, начатого в 2005 г. с целью прогноза последствий сельскохозяйственного использования земель. В условиях многофакторного стационарного опыта по изучению поверхностно-отвальной системы обработки, заложенного методом расщеплённых делянок с рендомизированным размещением вариантов в повторениях, проведены наблюдения за динамикой видового состава и численности микромицетов в зависимости от используемых агротехнологических приёмов, включающих системы основной обработки почвы и удобрений. Всего за период 2011–2015 гг. выявлено 22 рода и 101 вид микроскопических грибов. Анализ показал, что в агроценозах комплекс грибов несколько отличается от типичного для дерново-подзолистых почв естественных биоценозов. Состав доминирующей группы в целом за время исследований почти не изменялся и был представлен видами р. Penicillium. В число содоминантов входили зигомицетовые сапротрофы (Rhizopus nigricans Ehrenb., Mucor hiemalis Wehmer и виды р. Mortierella), смена которых в большей степени зависела от внешних условий. Часто обнаруживались грибы рр. Alternaria, Aspergillus, Cladosporium, Fusarium, Verticillium, содержащие фитопатогенные виды. Однако их встречаемость и численность не проявляли чёткой зависимости от таких факторов, как обработка почвы и внесение удобрений. Расчёт индексов биоразнообразия Шеннона и Пиилу показал, что при поверхностно-отвальной системе обработки в год вспашки разнообразие грибных комплексов снижается, происходит резкая их перестройка за счёт перемещения видов, обитающих в разных по глубине слоях почвы. Подобные изменения касаются и численности микромицетов. Отмечено снижение КОЕ грибов, особенно на неудобренном фоне, после проведения вспашки. В целом, как при отвальной, так и поверхностно-отвальной системах обработки показано возрастание численности микромицетов при внесении соломы 3 т/га + NPK. Запаханная на глубину пахотного горизонта солома с минеральными удобрениями, являясь хорошим питательным субстратом для грибов, на большинстве вариантов приводила к увеличению их количества. The results of monitoring the state of soil mycobiota started in 2005 with the aim of predicting the consequences of agricultural land use are presented. Under the conditions of a complex stationary experiment on the study of a surface-moldboard tillage system, laid down by the method of split plots with a randomized block design of variants in repetitions, observations were made of the dynamics of the species composition and number of micromycetes, depending on the agricultural technological methods used, including the systems of basic tillage and fertilizers. Total for the period 2011–2015 22 genera and 101 species of microfungus have been identified. The analysis showed that in agrocoenosis the complex of fungi is slightly different from the natural biocoenosis typical for soddy podzolic soils. The composition of the dominant group as a whole remained almost unchanged during the studies and was represented by the species of the Penicillium. The codominants included zygomycete saprotrophs (Rhizopus nigricans Ehrenb., Mucor hiemalis Wehmer and species of Mortierella), the change of which was more dependent on external conditions. Fungi Alternaria, Aspergillus, Cladosporium, Fusarium, Verticillium containing phytopathogenic species were often found. However, their occurrence and number did not show a clear dependence on such factors as tillage and fertilization. The calculation of the Shannon and Pielou biodiversity indices showed that with a surface-moldboard system of tillage in a year of plowing, the variety of fungal complexes decreases, and their sharp restructuring occurs due to the movement of species living in layers of soil different in depth. Such changes concern the number of micromycetes. A decrease in CFU of fungi was noted, especially on an unfertilized background after plowing. In general, both moldboard and surface-moldboard tillage systems show an increase in the number of micromycetes with the introduction of straw 3 t/ha + NPK. Straw plowed under the depth of the plough-layer with mineral fertilizers, being a good nutrient substrate for mushrooms, in most cases led to an increase in their amount.