Social Behaviour in Marine Microbes

Study Notes

Microbes exhibit complex social behaviours, not unique to humans or complex animals.
Social interactions observed in bacteria include communication and decision-making, cheating, bullying, helping, suicide, aggression, and families helping each other.
Understanding these interactions can help develop advanced biotechnology and medicinal applications.
Social behaviour in bacteria and viruses has evolved due to advantages in cooperation. These led to a selective advantage.
Social networks originated in bacteria.
Bacterial behaviour includes biofilm formation, extracellular matrix, differentiation into producers, cell chaining, and biofilm maturation.
The image shows complex microbial community structure such as spores, sporulating cells, D-amino acids, polyamines, motile cells, and differentiation into matrix producers and cell chaining.

Lecture Outline

Key questions posed by the lecturer regarding social interactions in microbes, including the types, their biological mechanisms, and their applications in biotechnology/medicine.

Behaviour Types

Complex communication/decision making.
Cheating.
Bullying
Helping others
Suicide
Aggression
Families helping each other
Selfish gene.

Evolution

Microbial behaviours are not unique to humans and even other complex animals.
These behaviours can be observed in bacteria and even viruses.
During evolution, the advantage of working together was clear, leading to selective advantages.
Social networks developed in bacteria.

Quorum Sensing (Revision)

Gram-positive bacteria use peptides for quorum sensing, which is density-dependent.
Gram-negative bacteria use small molecules (like AHLs) and also has density-dependent quorum sensing. Many examples include Vibrio fischeri.
Quorum sensing in gram-negative organisms involves a transcriptional activator protein (R protein) and an autoinducer (AHL) molecule produced by the autoinducer synthase.

Cell-Cell Communication by Airborne Signals

Ammonia signalling induces biofilm formation.
Ammonia also induces antibiotic resistance.

Bacterial Olfaction

Bacteria can sense their environment using olfaction, analogous to higher organisms.
Bacillus licheniformis respond behaviorally to volatile molecules like ammonia in a coordinated way.

Biofilm Induction

Bacillus licheniformis DSM13 exhibits biofilm formation in microtitre plates when cultured in different media (MSgg, LB). Biofilm formation is dependent on distance between wells in plates.

Ammonia and Microbial Interactions

Spent supernatant from DSM13 cultures, grown in MSgg media over 39 hours, affects pH in surrounding plates.
Different concentrations of ammonia, result in different levels of effect.

Nanowires

Microbes have electrically conductive pili that can be used to communicate between cells and as a terminal electron acceptor.
Cells may communicate by using these pili.
Information sharing, and biotechnological applications are considerations surrounding this function.

Conclusions

Microbes demonstrate complex social behaviours.
Quorum sensing and olfaction are examples of these mechanisms.
Understanding these systems helps to combat microbes by hindering their ability to communicate.
Bacteria have already developed sophisticated methods for interacting.

Description

This quiz explores the complex social behaviours exhibited by marine microbes, highlighting interactions such as communication, cooperation, and competition. Understanding these behaviours reveals insights into microbial communities and their applications in biotechnology and medicine. Dive into the fascinating world of microbial social dynamics and their evolutionary advantages.