Leiden biologists narrow more than 8,000 marine microbe extracts to five compounds for scale-up

Divided out, the team's figures come to about 20 biological tests per extract ^[1] and six or seven extracts per strain ^[2]. Five compounds from more than 8,000 extracts means each candidate stands for more than 1,600 extracts ^[3]. An extract is a mixture that can hold many compounds. The ratio shows how far the pool was narrowed and cannot be read as a per-molecule hit rate.

Mariana Avalos Garcia, the project manager, compared the task to looking for a needle in a haystack ^[1][5]. Her reason for searching marine microbes at all is their chemistry. "Marine ecosystems are particularly promising," she said ^[3]. "The organisms there have developed unique ways of surviving intense competition, disease pressure and environmental stress. In doing so, they often produce new compounds to protect themselves, and these can be very different from those found on land." ^[4]

The thing this account doesn't tell you is how well the sorting worked. It does not describe how the tool ranks samples, report a hit rate, or name the target pathogens and effective doses. The team is still confirming the five compounds' chemical structures and activity ^[12], so it is not yet settled whether any of them is new to science. I think the team's numbers support putting the bottleneck at sorting, with one condition. Narrowing more than 160,000 tests to five candidates ^[9][11] only counts as a success if those five survive structure confirmation.

The next stage is about supply: whether the substances can be produced sustainably at larger scale ^[11]. In fermentation, microorganisms are grown under controlled conditions so that they make the desired compound ^[13]. The group is improving that process alongside the structure work ^[12]. Growing strains in the lab is meant to avoid repeatedly collecting sponges and other organisms from the sea ^[14]. "Biodiscovery only makes sense if it doesn't harm or undermine the biodiversity it depends on," Avalos Garcia said ^[15].

The elicitor work points at a limit of the screen itself. Some microbes carry gene clusters for interesting compounds that stay switched off in culture ^[16]. That means the 8,000-plus extracts ^[8] capture what the strains made in the lab, which is only part of what their genomes encode. "Microorganisms often contain a library full of books, but most of those books are locked," Avalos Garcia said. "Finding an elicitor is like finding the key that lets you open those unread books." ^[18]

The applications are conditional. According to the Leiden account, new medicines, crop protection products and treatments for fish diseases could have their origins on the seabed ^[22]. Within MARBLES, bioinformaticians led by Marnix Medema worked on how the microbes suppress disease-causing organisms ^[23][19]. The project also trained dozens of Ph.D. candidates and postdoctoral researchers ^[21].