Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2024 Jun 19;29(12):2914.
doi: 10.3390/molecules29122914.

Preliminary Screening on Antibacterial Crude Secondary Metabolites Extracted from Bacterial Symbionts and Identification of Functional Bioactive Compounds by FTIR, HPLC and Gas Chromatography-Mass Spectrometry

Gobinath Chandrakasan  1 , Juan Fernando García-Trejo  1 , Ana Angelica Feregrino-Pérez  1 , Humberto Aguirre-Becerra  1 , Enrique Rico García  1 , María Isabel Nieto-Ramírez  1
Affiliations

Preliminary Screening on Antibacterial Crude Secondary Metabolites Extracted from Bacterial Symbionts and Identification of Functional Bioactive Compounds by FTIR, HPLC and Gas Chromatography-Mass Spectrometry

Gobinath Chandrakasan et al. Molecules. .

Abstract

Secondary metabolites, bioactive compounds produced by living organisms, can unveil symbiotic relationships in nature. In this study, soilborne entomopathogenic nematodes associated with symbiotic bacteria (Xenorhabdus stockiae and Photorhabdus luminescens) were extracted from solvent supernatant containing secondary metabolites, demonstrating significant inhibitory effects against E. coli, S. aureus, B. subtilus, P. mirabilis, E. faecalis, and P. stutzeri. The characterization of these secondary metabolites by Fourier transforms infrared spectroscopy revealed amine groups of proteins, hydroxyl and carboxyl groups of polyphenols, hydroxyl groups of polysaccharides, and carboxyl groups of organic acids. Furthermore, the obtained crude extracts were analyzed by high-performance liquid chromatography for the basic identification of potential bioactive peptides. Gas chromatography-mass spectrometry analysis of ethyl acetate extracts from Xenorhabdus stockiae identified major compounds including nonanoic acid derivatives, proline, paromycin, octodecanal derivatives, trioxa-5-aza-1-silabicyclo, 4-octadecenal, methyl ester, oleic acid, and 1,2-benzenedicarboxylicacid. Additional extraction from Photorhabdus luminescens yielded functional compounds such as indole-3-acetic acid, phthalic acid, 1-tetradecanol, nemorosonol, 1-eicosanol, and unsaturated fatty acids. These findings support the potential development of novel natural antimicrobial agents for future pathogen suppression.

Keywords: GC–MS; HPLC; PCR; antibacterial activity; entomopathogenic nematodes; symbiotic bacteria.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

Figures

Figure 1
Figure 1
The general view on natural antibacterial crude secondary metabolites extracted from bacterial symbionts and identification of functional bioactive compounds by FTIR and gas chromatography–mass spectrometry.
Figure 2
Figure 2
(A) Recovered soil entomopathogenic nematodes’ molecular characterization (strains 05 and 10); (B) extracted symbiotic bacteria molecular characterization (strains 05 and 10). BLAST search indicated more than 98% similarity between the sequences of the PCR product and the recovered sample. The sequence of the phylogenetic tree was constructed by Untitled Clustal W (Slow/Accurate, IUB).
Figure 3
Figure 3
The FTIR analysis of bacterial crude compounds of (A) X. stockiae and (B) P. luminescens.
Figure 4
Figure 4
GC–MS chromatogram of X. stockiae.
Figure 5
Figure 5
GC–MS chromatogram of P. luminescens.
Figure 6
Figure 6
Screening of antibacterial effect on X. stockiae fractionated compounds using HPLC analysis at different concentrations (25 µL, 50 µL, 75 µL, 100 µL, and standard antibiotics). Bacterial pathogens: (A) E. coli, (B) S. aureus, (C) B. subtilus, (D) P. mirabilis, (E) E. faecalis, and (F) P. stutzeri; (G) bar graph indicating ZOI of bacterial pathogens with bioactive substances of X. stockiae.
Figure 6
Figure 6
Screening of antibacterial effect on X. stockiae fractionated compounds using HPLC analysis at different concentrations (25 µL, 50 µL, 75 µL, 100 µL, and standard antibiotics). Bacterial pathogens: (A) E. coli, (B) S. aureus, (C) B. subtilus, (D) P. mirabilis, (E) E. faecalis, and (F) P. stutzeri; (G) bar graph indicating ZOI of bacterial pathogens with bioactive substances of X. stockiae.
Figure 7
Figure 7
Screening of antibacterial effect on P. luminescens fractionated compounds using HPLC analysis at different concentrations (25 µL, 50 µL, 75 µL, 100 µL, and standard antibiotics). Bacterial pathogens: (A) E. coli, (B) S. aureus, (C) P. stutzeri, (D) E. faecalis, (E) P. mirabilis, and (F) B. subtilus; (G) bar graph indicating ZOI of bacterial pathogens with bioactive substances of P. luminescens.
Figure 7
Figure 7
Screening of antibacterial effect on P. luminescens fractionated compounds using HPLC analysis at different concentrations (25 µL, 50 µL, 75 µL, 100 µL, and standard antibiotics). Bacterial pathogens: (A) E. coli, (B) S. aureus, (C) P. stutzeri, (D) E. faecalis, (E) P. mirabilis, and (F) B. subtilus; (G) bar graph indicating ZOI of bacterial pathogens with bioactive substances of P. luminescens.
Figure 8
Figure 8
The general mechanisms of antimicrobial action on bioactive functional compounds from symbiotic bacteria.
See this image and copyright information in PMC

Similar articles

See all similar articles

References

    1. Gobinath C., Rodríguez-Hernández A.I., del Rocío López-Cuellar M., Palma-Rodríguez H.M., Chavarría-Hernández N. Bacteriocin encapsulation for food and pharmaceutical applications: Advances in the past 20 years. Biotechnol. Lett. 2019;41:453–469. - PubMed
    1. Newman D.J., Cragg G.M. Natural products as sources of new drugs over the 30 years from 1981 to 2010. J. Nat. Prod. 2012;75:311–335. doi: 10.1021/np200906s. - DOI - PMC - PubMed
    1. Ji D., Yi Y., Kang G.H., Choi Y.H., Kim P., Baek N.I., Kim Y. Identification of an antibacterial compound, benzylideneacetone, from Xenorhabdus nematophila against major plant-pathogenic bacteria. FEMS Microbiol. Lett. 2004;239:10–15. doi: 10.1016/j.femsle.2004.08.041. - DOI - PubMed
    1. Bode H.B. Entomopathogenic bacteria as a source of secondary metabolites. Curr. Opin. Chem. Biol. 2009;13:224–230. doi: 10.1016/j.cbpa.2009.02.037. - DOI - PubMed
    1. Shi Y.M., Hirschmann M., Shi Y.N., Ahmed S., Abebew D., Tobias N.J., Grün P., Crames J.J., Pöschel L., Kuttenlochner W., et al. Global analysis of biosynthetic gene clusters reveals conserved and unique natural products in entomopathogenic nematode-symbiotic bacteria. Nat. Chem. 2022;14:701–712. doi: 10.1038/s41557-022-00923-2. - DOI - PMC - PubMed

MeSH terms

Substances

Grants and funding

This research received no external funding.