Important Lessons From the Bacterial Equivalent of Human Society

07/06/2014 11:49 EDT | Updated 09/05/2014 05:59 EDT

In almost every branch of the life sciences, diversity is a key to success. From an anthropological perspective, variation maintains a strong and resilient species. Biological diversification has played a significant role in the origin and evolution of humans bringing us to where we are today. The social and economic value of a varied community is also well known and is the basis for strategies moving ahead into the future.

Not surprisingly, diversity also works in the microbial world. For the last few decades, researchers have taken the same principles attributed to human success and searched the bacterial equivalent -- Escherichia coli -- for similarities and possibly avenues to predict our future. The reason: time. For us, diversity may take centuries and millennia to witness. For bacteria, it's a matter of days and weeks.

One of the first studies happened in 1987 with the identification of diversity among E. coli cells within a population. From a human's eye view, the bacterial cities - known as colonies - all looked to be the same, under closer examination, there was a microcosm of sectors. Each acted independently from the other and yet together made the entire populace better. Extracting any of these areas would in essence hurt the overall population and potentially lead to its demise.

The idea behind having diversity within a single species was explored further and by 1998, the concept of the insurance hypothesis was developed. In essence, diversity increases the richness of a species such that it can withstand environmental changes - both good and bad. In this natural mechanism of survival, unless an extinction event occurs, there can be no significant die-off leading to the continuation of the species. There of course was a drawback: inequality and a change towards re-segregation in the absence of crises. Unfortunately, there was little way to prove this as human historical records only go back a few hundred generations.

From the perspective of E. coli, variety would allow for survival under extreme conditions such as the presence of killing agents including heat, ultraviolet light and antibiotics. In addition, a diverse populace would also help to propagate the species during the good times allowing for construction of solid infrastructure known as biofilms, development of efficient sharing of nutrient wealth, and an increase in the bacterial equivalent of intimacy, conjugation.

Though the hypothesis was made, actual investigations were few in number. But last week, a French team of researchers revealed the results of just such a study with E. coli. The group looked at single colonies over a period of three weeks - equivalent to some 30,000 human years - to identify both genetic and physical differences between the individual cells. What they found proved the hypothesis as well as provided us with a few significant clues regarding our own future.

While initially all the cells were the same, over 4 days - 5,000 human years - significant changes in the populace were seen. Some of the bacteria mutated to develop new traits - islands - to give them a particular advantage over certain types of environmental change. The abilities included antibiotic resistance, better nutrient utilization, resistance against temperature changes, and formation of stable biofilms.

Overall, the initial results showed E. coli developed a civilized society in about the same time it took for humans. The data also revealed a potentially excellent community to deal with any change. Yet, there was more to the story. As time went on without any significant environmental event, the landscape changed. Competition became the rule and the bacteria began to antagonize rather than complement each other.

In terms of statistics, 12 per cent grew antibiotic resistance and became marginalized from others. Twenty-eight per cent of the population chose a wealthy style, happily living in their gated biofilms. Half of all the bacteria decided to take a middle-class lifestyle, choosing an easy nutrient source and never engaging in any extreme activity. The rest simply died as a result of an inability to keep up. Though diversity was still present, the richness declined. If the trend continued past the three week limitation of the experiment, the population would eventually be unable to deal with a natural catastrophe.

The links of this study to our human realities are not difficult to appreciate. Much like E. coli, we have developed a highly diverse community with the ability to deal with almost any natural crisis. But as seen in the experiments, this could all change for the worse.

Inasmuch as we encounter several environmental concerns each year, nothing has forced us to forgo socially accepted segregation. As a result, there is an ever increasing wealth gap leaving many people without the ability to thrive, let alone survive; we develop technologies for use as weapons against other humans, not as prevention against impending terrestrial threats; and we continue to look at race as a basis for separation rather than accept all humans as one diverse species. Though the bacterial context suggests the consequences of these activities should be thousands of human equivalent years down the road, we may already nearing that threshold.

Perhaps it might be time to take a lesson from E. coli and learn to embrace the diversity of humanity. As the bacterium has shown us, if we don't, we may find ourselves losing out as a species in the future and worse, woefully unprepared should the unthinkable catastrophe, whether physical, biological or chemical, occur.


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