Solid-liquid Interface Screening SystemーApplication to the Screening of Antibiotic and Cytotoxic Substance-producing Fungi

Our plain-English summary of Solid-liquid Interface Screening SystemーApplication to the Screening of Antibiotic and Cytotoxic Substance-producing Fungi, by S. Oda, S. Nomura, M. Nakagawa, et al (Biocontrol Science, 2019).

The study

• Authors: S. Oda, S. Nomura, M. Nakagawa, K. Shin-Ya, N. Kagaya, T. Kawahara
• Journal: Biocontrol Science
• Published: 2019;24(1):47-56
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A useful tool for the screening of fungi producing biologically active secondary metabolites such as antibiotics and cytotoxic substances has been developed. An agar plate-organic solvent interface cultivation (A/S-IFC) system, which comprised a hydrophobic organic solvent (upper phase) , a fungal mat (middle phase) and an agar plate (lower phase) , was constructed. The metabolite profiles were compared among the A/S-IFC, a traditional submerged cultivation (SmC) and an extractive liquid surface immobilization (Ext-LSI) system consisted of a hydrophobic solvent (upper phase) , a fungal cells-ballooned microspheres (middle phase) and a liquid medium (lower phase) , with high-performance liquid chromatography-photodiode array detector (HPLC-PDA) . In the A/S-IFC, many hydrophobic metabolites vastly different from those in the SmC were accumulated in the organic phase as with the Ext-LSI. For example, a valuable azaphilone, sclerotiorin, was remarkably produced into the organic phase in the A/S-IFC. The A/S-IFC was applied to the screening of antibiotic-producing fungi. As a result of paper disk method, it was found that 321 isolated among 811 strains produced antifungal metabolites (hit rate, 39.6%) . Furthermore, 8, 23, and 30 strains also produced cytotoxic metabolites against SKOV-3 (human ovary adenocarcinoma) , MESO-1 (human malignant pleural mesothelioma) , and Jurkat cells (immortalized human T lymphocyte) .

In plain English

This was a laboratory study of a way to grow fungi in order to find strains that make antibiotic or cell-killing substances. It did not study asbestos exposure or people. Mesothelioma appears only as one of three human cell lines grown in the lab. The authors grew fungal mats on agar plates under a layer of silicone oil and used seven fungal strains to compare this system with two other culture methods. Fungi grown this way released many water-repelling substances into the oil, and these differed from what ordinary shaken liquid cultures made. One of them, sclerotiorin, was identified from Penicillium multicolor. The method was then used to screen 811 fungal isolates. Extracts from 321 showed activity against a test fungus, Wickerhamomyces anomala (hit rate 39.6%). Extracts from 8, 23 and 30 strains brought cell viability below 25% in SKOV-3 ovary adenocarcinoma cells, MESO-1 malignant pleural mesothelioma cells and Jurkat T lymphocyte cells, respectively. The methods state that the 811 isolates were assessed for both antifungal and cytotoxic activity. The authors concluded that the method has advantages over the other two systems.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory methods study (fungal cultivation and screening experiments), not a study of people or of asbestos
• Who was studied: Seven named fungal strains for the comparison of culture methods, plus 811 isolated fungal strains assessed for antifungal and cytotoxic activity; three human cell lines (SKOV-3, MESO-1, Jurkat) used in the cytotoxicity test
• Exposure: No asbestos exposure was studied. Extracts of fungal metabolites from the agar plate-organic solvent interface culture were added to cultured human cell lines (at 0.5% for 72 h) and to paper disks on plates of a test fungus
• Main results:
  • In the screen of 811 isolates, metabolites from 321 showed antifungal activity against Wickerhamomyces anomala NBRC 10213 (halo diameter 11-36 mm), a hit rate of 39.6%
  • 8, 23 and 30 strains produced metabolites cytotoxic to SKOV-3 (human ovary adenocarcinoma), MESO-1 (human malignant pleural mesothelioma) and Jurkat (immortalized human T lymphocyte) cells, respectively, defined as cell viability below 25%; the results say 'among fungi tested', and the methods state that the 811 isolates were assessed for cytotoxic activity
  • In all strains compared, hydrophobic metabolites were found in the organic (oil) phases of the two interface systems, while hydrophilic metabolites accumulated in the aqueous phases
  • In Penicillium multicolor IAM 7153 a metabolite (peak 8) was identified as sclerotiorin; its accumulation was higher in the organic phase of the extractive liquid-surface system than in the agar plate-solvent system
• The authors' conclusion: The authors concluded that the agar plate-organic solvent interface cultivation system has advantages over submerged culture and the extractive liquid-surface system, such as distinctive hydrophobic metabolite profiles, high production, easy recovery and possible use with slow-growing fungi and actinomycetes

Topics

Medical terms in this study, explained in our Lexicon: Adenocarcinoma, Pleural Mesothelioma.

Related studies

• Bioweathering of chrysotile by fungi isolated in ophiolitic sites — S. Daghino, E. Martino, et al. (2008)
• Free radical generation at the solid/liquid interface in iron containing minerals — B. Fubini, L. Mollo, et al. (1995)
• Determination of 5,10,15,20-tetra-(m-hydroxyphenyl)chlorin in human plasma by high performance liquid chromatography — Q. Wang, H.B. Ris, et al. (1993)
• Three potential sources of microfungi in a treated municipal water supply system in sub-tropical Australia — N.B. Sammon, K.M. Harrower, et al. (2011)
• Occurrence of heavy metal-resistance in microflora from serpentine soil of Andaman — A. Pal, S. Dutta, et al. (2005)
• BAMLET kills chemotherapy-resistant mesothelioma cells, holding oleic acid in an activated cytotoxic state — E.M. Rath, Y.Y. Cheng, et al. (2018)

Browse return to medical research.