Complex sentence: The link between mycobactins, iron-chelating growth factors from mycobacteria, and iron was first made in the 1960s, as interest grew regarding the application of mycobactins as target molecules for a rational anti-tuberculosis agent.
Split into simpler sentences: The link between mycobactins, iron-chelating growth factors from mycobacteria, and iron was first made in the 1960s. At the time, interest was growing in resolving an application of mycobactins as target molecules for a rational anti-tuberculosis agent.