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Mysterious biofilms: How do they survive in extreme environments?
Biofilms, a fascinating community of microorganisms, are ubiquitous in natural, industrial and hospital environments. These microorganisms are not just single cells floating in the water; they exist like miniature "cities" that are connected to each other, attached to certain surfaces, and wrapped in a sticky extracellular matrix. This matrix is key to the collaborative survival of most microorganisms and helps them adapt to harsh environments.
Biofilms are composed of extracellular polymers (EPSs) secreted by microorganisms themselves, which include components such as sugars, proteins, lipids and DNA.
The formation and evolution of biofilm
The origin of biofilm can be traced back to 3.3 billion years ago, when the earth's environment was extremely harsh. This structure not only helps prokaryotes survive, but also promotes complex interactions between cells. Initially, these microorganisms rely on weak van der Waals forces and hydrophobicity to adhere to each other on a surface, and then develop stronger attachment structures such as pili or specialized attachment filaments.
The biofilm formation process can be divided into several main stages. The first step is for free-swimming microorganisms to attach to a surface and, over time, they grow rapidly through cell division and the addition of new members.
These microbes communicate with each other primarily through "quorum sensing," which allows them to coordinate their behavior and reproduce together.
Properties and adaptability of biofilms
Inside a biofilm, the physiological characteristics of microorganisms are completely different from those of cells in a planktonic state. Studies have shown that the resistance of microorganisms in biofilms to the outside world and their ability to resist antibiotics can increase by up to 5,000 times. This powerful adaptability is because the extracellular matrix can effectively protect the microorganisms within the membrane from harmful external factors.
At the same time, biofilms are constantly evolving to cope with intense environmental challenges. Effective sharing of food, intervention of the immune system and diverse microscopic community structures allow these microorganisms to display amazing survival skills.
In some cases, microorganisms inside biofilms can more quickly develop resistance to pathogens, making them more robust in extreme environments.
Biofilms in extreme environments
The adaptability of biofilms enables them to survive in a variety of extreme environments, such as high temperatures, salinity, or waters with extreme pH values. In these environments, biofilms can not only exist stably, but also continue metabolic processes and show strong tolerance to changes in the surrounding environment.
For example, some archaea can grow in oxygen-free groundwater, and the "fibers" in their structures (such as hami) are important for their attachment and interaction.
Dispersion and reuse of biofilm
The dispersion process is crucial to the life cycle of biofilms, allowing cells to break away from the original biofilm and find new living space. Scientists have found that certain enzymes, such as deoxyribonucleases, can effectively degrade the extracellular matrix of biofilms and promote the dispersion of cells, which helps the formation and implantation of new biofilms.
Microbes in the process of dispersion will display different characteristics, such as selectively activating corresponding genes to improve their chances of survival in terms of responding to the immune system and infection.
Conclusion
Biofilm is not just an aggregate of some microorganisms, but also an ecosystem with complex functions and interdependence. Their diversity and adaptability constantly challenge our understanding of life forms, prompting us to think about what attitudes and methods we should adopt in scientific research, better utilization and solving related problems when facing these microorganisms. ?
