Secretions Are Antibacterial

an irisdescent green fly with red eyes sits on a bright yellow flower

Biological Strategy

Sheep blow fly

AskNature Team

Image: Mabel Amber / Pixabay / Free non-commercial use

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

Insects

Class Insecta (“an insect”): Flies, ants, beetles, cockroaches, fleas, dragonflies

Insects are the most abundant arthropods—they make up 90% of the animals in the phylum. They’re found everywhere on earth except the deep ocean, and scientists estimate there are millions of insects not yet described. Most live on land, but many live in freshwater or saltwater marshes for part of their life cycles. Insects have three distinct body sections: a head, which has specialized mouthparts, a thorax, which has jointed legs, and an abdomen. They have well-developed nervous and sensory systems, and are the only invertebrate that can fly, thanks to their lightweight exoskeletons and small size.

Search this Living System

Secretions of the greenbottle fly protects the larvae from bacteria via antibacterial peptides.

Image: Alvesgaspar / Wikimedia Commons /

A green-bottle fly (''Lucilia sericata'')

Image: Alvesgaspar / Wikimedia Commons /

Fly of the Calliphoridae family (Lucilia caeser)

Image: Dahola / Wikimedia Commons /

1=Green bottle fly in Northeinwestfalen / Germany

“In conclusion, this preliminary investigation has shown that the secretions from L. sericata larva possess significant antibacterial activity against a range of Gram-positive microorganisms, including some clinically important strains of MRSA. The activity/activities in this secretion were considered to be of low molecular weight, highly stable and a systemic part of the larva. They possess several characteristics consistent with insect antibacterial peptides. All these features point to the possible presence of compounds within the larval secretions of L. sericata that could prove highly useful in the fight against MRSA and other nosocomial infections.” (Kerridge et al. 2005:336)

Last Updated August 18, 2016

References

Journal article

Antibacterial properties of larval secretions of the blowfly, Lucilia sericata

Medical and Veterinary Entomology | 30/08/2005 | A. Kerridge, H. Lappin-Scott, J. R. Stevens

embedly preview

AskNature