Compounds Inhibit Bacteria

bright green leafs sprout from rich dark soil

Biological Strategy

Garden pea

AskNature Team

Image: Diyana Dimitrova / Shutterstock / Some rights reserved

Protect From Microbes

In living systems, microbes play important roles, such as breaking down organic matter and maintaining personal and system health. But they also pose threats. Bacteria can be pathogens that cause diseases. Some bacteria create colonies called biofilms that can coat surfaces, reducing their effectiveness–for example, inhibiting a leaf’s ability to photosynthesize. Living systems must have strategies for protecting from microbes that cause disease or become so numerous that they create an imbalance in the system. At the same time, living systems must continue living in harmony with other microbes. Some living systems kill microbes. Others repel without killing to reduce the chances that microbes will adapt to the lethal strategy and become resistant to it. For example, some pea seedlings exude a chemical that inhibits biofilm buildup.

Search this Function

Flowering Plants

Clade Angiosperms (“receptacle seed”): Dandelions, oaks, grasses, cacti, apples

With 416 families containing some 300,000 known species, angiosperms are the most diverse group of plants, and they can be found around the globe in a wide variety of habitats. They are characterized by seeds that grow enclosed in ovaries, which are enclosed in flowers. The floral organs then develop into fruits of myriad kinds and dimensions, from simple seed casings on maples to elaborate fleshy growths like papayas. The oldest flower known from fossils, Montsechia vidalii, appeared during the Jurassic Period 130 million years ago. They are the primary food source for herbivorous animals, which in turn makes them the indirect food source for carnivores as well.

Search this Living System

Pea seedlings inhibit bacterial biofilm formation by exuding a unique chemical compound.

“Recently, Bauer and colleagues showed that exudates from pea seedlings (Pisum sativum) and other plant sources (including the unicellular soil-freshwater alga, Chlamydomonas reinhardtii) were found to contain a range of compounds that mimicked N-acyl-HSL signals in several bacterial reporter strains (reviewed in ref. 41). In some cases, these extracts inhibited quorum sensing dependent phenotypes, suggesting that the active compounds may have potential as quorum sensing-blockers. Although the chemical nature of the active mimic compounds is not (yet) known, they are apparently not N-acyl-HSL.” (Welch et al. 2005:201)