Mapping Vital Compounds in the Caterpillar Fungus with Advanced Imaging

Jenn Hoskins
18th February, 2024

Mapping Vital Compounds in the Caterpillar Fungus with Advanced Imaging

Cordyceps cicadae

Photo adapted from: Atsushi Nakajima / CC BY (Source)
Cordyceps cicadae is a medicinal fungus traditionally used in Chinese medicine, valued for its potential health benefits. Ensuring the quality and understanding how its active compounds are distributed within the organism is crucial for effective use. Historically, analyzing these compounds required breaking down the fungus, losing information about where they naturally occur within its structure. Researchers at Chengdu University of Traditional Chinese Medicine[1] have developed a new method to visualize the distribution of various compounds directly within the Cordyceps cicadae, offering a more complete understanding of its chemical makeup. The study focused on two main parts of the fungus: the sclerotium and the coremium. The sclerotium is the dense, hardened structure, while the coremium is the inner, softer tissue where the fungal filaments grow. The goal was to map the location of different metabolites – the chemicals produced by the fungus – within these parts, including nucleosides, amino acids, polysaccharides, organic acids, and fatty acids. The researchers employed a technique called desorption electrospray ionization mass spectrometry imaging (DESI-MSI). DESI-MSI works by spraying a fine mist onto a frozen sample of the fungus. This mist helps to release molecules from the surface, which are then analyzed by a mass spectrometer. A mass spectrometer measures the mass-to-charge ratio of these molecules, allowing scientists to identify them. Crucially, the technique also records where on the sample each molecule was detected, creating a visual map of its distribution. This is a significant advancement over traditional methods, which require the sample to be dissolved, destroying the spatial information. The analysis identified a total of 62 different compounds. The results revealed distinct patterns of metabolite distribution. For example, nucleosides – building blocks of DNA and RNA – were concentrated in the coremium, while peptides (short chains of amino acids) were primarily found in the sclerotium. Sugars and sugar alcohols also showed a preference for the coremium. Organic acids and fatty acids, however, were more abundant in the nucleus of the fungus than in the sclerotium. Other amino acids didn’t show a clear pattern of distribution. This approach builds on similar work done with other medicinal plants. For instance, studies using DESI-MSI have successfully mapped the distribution of ginsenosides in ginseng, showing how their location varies depending on the age and part of the plant[2]. Similarly, research on Rauvolfia tetraphylla used DESI-MSI to pinpoint the location of indole alkaloids within the plant’s fruits, leaves, and roots[3]. These studies demonstrate the power of DESI-MSI for understanding the chemical geography of medicinal plants. The findings also echo observations made with Aconitum L., where different alkaloids are unevenly distributed within the plant’s tissues[4]. Understanding these distributions is vital, as the concentration of specific compounds directly impacts both the therapeutic effect and potential toxicity of the herb. The current study, like the Aconitum L. research, highlights the importance of considering spatial distribution when evaluating the quality and efficacy of a medicinal plant. The method developed by the Chengdu University of Traditional Chinese Medicine team is described as simple and fast, offering a significant advantage over traditional analytical techniques. By visualizing the spatial distribution of metabolites, this research provides valuable insights into the metabolic network of Cordyceps cicadae. This information can be used to improve quality control measures and further investigate how the fungus produces its beneficial compounds over time and in different locations within the organism.

BiochemPlant ScienceMycology

References

Main Study

1) Tissue distribution of metabolites in Cordyceps cicadae determined by DESI-MSI analysis.

Published 17th February, 2024

https://doi.org/10.1007/s00216-024-05188-x

Related Studies

2) Localization of constituents for determining the age and parts of ginseng through ultraperfomance liquid chromatography quadrupole/time of flight-mass spectrometry combined with desorption electrospray ionization mass spectrometry imaging.

https://doi.org/10.1016/j.jpba.2020.113722

3) UPLC and ESI-MS analysis of metabolites of Rauvolfia tetraphylla L. and their spatial localization using desorption electrospray ionization (DESI) mass spectrometric imaging.

https://doi.org/10.1016/j.phytochem.2018.11.009

4) Spatial distribution and comparative analysis of Aconitum alkaloids in Fuzi using DESI-MSI and UHPLC-QTOF-MS.

https://doi.org/10.1039/d2an02051c


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