# One Strain Many Compounds Approach for Anti-Trypanosoma cruzi Compounds: Empowering the Marine Bacterium Metabacillus indicus

## TL;DR

This study explores how changing cultivation conditions of a marine bacterium can boost its production of compounds effective against Chagas disease.

## Contribution

The study demonstrates that the OSMAC approach can enhance anti-Trypanosoma cruzi metabolite production in Metabacillus indicus.

## Key findings

- Cultivation in Marine Agar increased antitrypanosomal potency by 8.4-fold.
- Cobalt-60 γ radiation improved metabolite potency by 2-fold.
- NMR and UHPLC-ESI-HR-MS/MS analysis revealed diverse metabolomic profiles.

## Abstract

Neglected tropical
diseases as Chagas disease (CD) affect
more
than eight million people, mainly in the Americas, causing fatal cardiovascular
outcomes. Relying on two old, toxic, and low efficacy drugs for treatment,
there is an urgent need for new candidates. Comprising a high chemodiversity,
marine bacteria are a rich source of small molecules with potential
against human pathogens. Cultivation-based strategies of bacteria,
such as the one strain many compounds (OSMAC) approach, have proven
to be a simple and promising tool for drug discovery, with the ability
to stimulate the expression of cryptic genes in microorganisms. In
this study, using the OSMAC, we evaluated the potential of the marine
bacteria Metabacillus indicus to produce
anti-Trypanosoma cruzi compounds with
higher potency. The M. indicus was
cultivated under different conditions, subdivided into four groups,
as nutritional, physical, biological, and chemical alterations. For
comparisons, the extract obtained from the bacteria in Marine Broth
(static) at 25 °C was used as a control and resulted in an EC50 value of 28 μg/mL against the trypomastigotes. The
physical alterations proved to be the most effective approach to improve
the potency of M. indicus metabolites,
resulting in EC50 values between 3 and 26 μg/mL.
The cultivation in Marine Agar potentiated the antitrypanosomal metabolites
by 8.4-fold. When exposed to cobalt-60 γ radiation (0.5 kGy),
the bacteria produced metabolites with 2-fold higher antitrypanosomal
potency. The nutritional alterations resulted in potent metabolites,
with EC50 values between 11 and 18 μg/mL, while biological
alterations resulted in EC50 values between 11 and 28 μg/mL.
Addition of T. cruzi and Leishmania infantum antigens and co-cultivation with Acinetobacter baumannii, enhanced by 2-fold the potency.
Chemical elicitors such as DMSO and EtOH demonstrated no improvements
for M. indicus cultivation. The chemical
profile of M. indicus was analyzed
using NMR and UHPLC-ESI-HR-MS/MS and processed using the GNPS platform,
which led to the annotation of nucleosides, dipeptides, steroids,
and fatty acid derivatives. These findings confirmed that the OSMAC
approach yielded not only distinct antitrypanosomal activities but
also distinct metabolomic profiles in M. indicus that could be exploited for drug discovery studies for Chagas disease.