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The secret life of E. coli: Why do they survive so easily in the intestines?
There are billions of bacteria living in our intestines, among which Escherichia coli is undoubtedly an important resident. This bacterium is a Gram-negative, facultative anaerobic, rod-shaped bacterium that is frequently found in the lower intestine of warm-blooded animals. Many strains of E. coli are part of the gut microbiome and are generally considered harmless or even beneficial to human health.
Certain strains of E. coli are able to produce vitamin K2 and prevent harmful pathogens from colonizing the intestines.
Under normal circumstances, E. coli only accounts for about 0.1% of the human intestine, but its importance cannot be ignored. These bacteria are able to form a symbiotic relationship with their hosts, jointly promoting the health of each other. However, not all E. coli are harmless and some serotypes such as enteropathogenic E. coli (EPEC) and enteropathogenic E. coli (ETEC) can cause serious food poisoning.
Biology and Biochemistry
E. coli cells have distinct morphological characteristics, usually rod-shaped, about 2.0 microns long and between 0.25 and 1.0 microns wide. Their cell walls consist of a thin peptidoglycan layer and an outer membrane, which is one reason why they appear pink when stained. The presence of the outer membrane makes them resistant to certain antibiotics, such as penicillin.
E. coli can reproduce rapidly under aerobic conditions, and it takes at least 20 minutes to complete a cell division.
The metabolic methods of Escherichia coli are also very diverse. They can use a variety of substrates for mixed acid fermentation to produce substances such as lactic acid, ethanol and carbon dioxide. This flexible metabolism allows them to survive in changing environments.
Adaptation and evolution
Escherichia coli has strong genetic adaptability. It can transfer genes through bacterial conjugation or transduction, thereby promoting the horizontal spread of genes. Some biological studies have shown that E. coli is only a carrier of gene recombination. As genes change, their characteristics may also change, thereby affecting pathogenicity.
E. coli has a high degree of genetic and phenotypic diversity, which allows scientists to track the source of environmental pollution based on the characteristics of different strains.
Scientists have been studying Escherichia coli for more than 60 years. These bacteria are not only important scientific research models in the fields of biotechnology and microbiology, but also play an important role in the detection of many environmental samples.
Relationship with the host
In natural ecosystems, the relationship between E. coli and its host is symbiotic. Although E. coli provide certain health benefits to the host, under inappropriate environmental conditions, they can also become pathogens and cause health problems to the host. In this case, transmission often occurs through foodborne routes, leading to food poisoning incidents in humans.
Understanding how E. coli survives in the intestines will help improve our understanding of microbial ecology and its impact on health.
Researchers have found that E. coli can survive and reproduce in a variety of different environments, which makes them play an important role in ecosystems. However, becoming a potential pathogen also reminds us that our relationship with these microorganisms is not simple, and sometimes small changes can affect our overall health. In this context, how much do you know about the survival of E. coli?
