Biotransformation of bromhexine by Cunninghamella elegans, C. echinulata and C. blakesleeana

Abstract Fungi is a well-known model used to study drug metabolism and its production in in vitro condition. We aim to screen the most efficient strain of Cunninghamella sp. among C. elegans, C. echinulata and C. blakesleeana for bromhexine metabolites production. We characterized the metabolites produced using various analytical tools and compared them with mammalian metabolites in Rat liver microsomes (RLM). The metabolites were collected by two-stage fermentation of bromhexine with different strains of Cunninghamella sp. followed by extraction. Analysis was done by thin layer chromatography, high performance thin layer chromatography, Fourier transform infrared spectroscopy, high performance liquid chromatography and Liquid chromatography–mass spectrometry. The role of Cytochrome P3A4 (CYP3A4) enzymes in bromhexine metabolism was studied. Fungal incubates were spiked with reference standard – clarithromycin to confirm the role of CYP3A4 enzyme in bromhexine metabolism. Three metabolites appeared at 4.7, 5.5 and 6.4 min retention time in HPLC. Metabolites produced by C. elegans and RLM were concluded to be similar based on their retention time, peak area and peak response of 30.05%, 21.06%, 1.34%, and 47.66% of three metabolites and bromhexine in HPLC. The role of CYP3A4 enzyme in metabolism of bromhexine and the presence of these enzymes in Cunninghamella species was confirmed due to absence of peaks at 4.7, 5.4 and 6.7 min when RLM were incubated with a CYP3A4 enzyme inhibitor – clarithromycin.

Bioremediation of PCP by Trichoderma and Cunninghamella Strains Isolated from Sawdust

Four fungal isolates, SD12, SD14, SD19 and SD20 isolated from the aged sawdust grew on agar plates supplemented with PCP up to a concentration of 100 mg L-1. At high PCP concentration, isolate SD12 showed the highest radial growth rate of 10 mm day-1, followed by SD14 and SD19 both with 4.5 mm day-1 and SD20 with 4.2 mm day-1. Ultrastructural study on the effect of PCP on the PCP tolerant fungi using scanning electron microscope showed that high concentration of PCP caused the collapse of both fungal hyphae and spores. Among the four PCP tolerant fungi examined, isolate SD12 showed the least structural damage at high PCP concentration of 100 mg L-1. This fungal isolate was further characterized and identified as Cunninghamella sp. UMAS SD12. Preliminary PCP biodegradation trial performed in liquid minimal medium supplemented with 20 mg L-1 of PCP using Cunninghamella sp. UMAS SD12 showed that the degradation up to 51.7% of PCP in 15 days under static growth condition.

Micoparasitismo biotrofico de Fusarium oxysporum sobre Cunnighamella sp / Biotrophic mycoparasitism of Fusarium oxysporum on Cunnighamella sp

Se describe un caso de micoparasitismo biotrófico de ocurrencia natural en el suelo, entre las hifas de una cepa de Fusarium oxysporum complex y Cunninghamella sp. Las hifas de F. oxysporum se desarrollaron sobre las células vivas del hospedador, mostrando 2 tipos de efectos parasíticos: uno de enrollamiento y otro de contacto con penetración de las hifas, sin la aparente eliminación del hospedador. Esta situación poco común en la literatura, demuestra las capacidades adaptativas de esta especie al micoparasitismo en grupos filogenéticamente distantes.

This paper describes a case of mycoparasitism naturally occurring, where Fusarium oxysporum parasitizes hyphae of Cunninghamella sp, to show mycoparasitism between the two fungi. This is a case of biotrophic mycoparasitism by contact. The hyphae of F. oxysporum developed closely along the living cells of the host showing mycoparasitic effect, some for a loop, and other contact with penetration of the hyphae. This situation is rare in the literature, demonstrates the adaptive capacities of this species to mycoparasitism in phylogenetically distant groups.