Tag Archives: microbe

How Bacteria May Be Our Allies in the War on Climate Change

A recent report from the United Nations has revealed some unsettling figures, warning that our planet could experience a 40 percent shortage of usable water by the year 2030 unless countries begin to substantially cut back on its usage. Because 70 percent of fresh water in the world is used on irrigation and agriculture, the most practical approach would be to change the ways in which people farm. The need is a rather ubiquitous one. Throughout California’s Central Valley, farmers have begun drilling for water, and they are now tapping into stores that are over 30,000 years old. Kenya is now being faced with its worst drought since 2000, and farmers have begun hand-digging wells in order to gain hold on the receding water table, meanwhile, it’s estimated that as many as one-in-ten Kenyans are going hungry.

This might seem to be as much that both of these regions have in common, but that means that a game-changing solution could easily be put into place in both economies, making use of a resource we hardly knew was there. Beneath the soil, surrounding the roots of plants are swarms of helpful bacteria that number in the billions. These microbiomes can be found in soil all across the globe: along the hard-hit Kenyan coast, right to New England’s notoriously rocky soil.

In each shovelful of dirt, there are armies of bacteria, along with microscopic fungi and protozoan, all of which carry out life processes that the soil is dependent upon for yielding crops, but bacteria substantially outnumber the other microorganisms. Even in bygone centuries, bacteria effectively provided us with a number of products – from cheeses, wines, and vinegars, to laundry detergents and even medicine. Now, it could seem that aside from a food source, they could be helpful allies in actually the growth of standard produce. Actinomyocytes – which are just one type of the diverse microscopic ecosystem found in the dirt, have been used to synthesize a number of modern day antibiotics, such as erythromycin, used to treat bronchitis and whooping cough, among many other infections.

Another type of bacteria known as pseudomonas, is able to metabolize a number of chemicals and fertilizers into useful nutrients for the soil, while clostridium is able to thrive despite an absence of oxygen, breathing anaerobically from the soil’s nitrogen supply as it feeds the plants their nutrients. Not only does this trait make it important, but it’s also an important sign that the bacteria, with their incredibly short lifespans, are among the few organisms that can adapt quickly to an ever changing climate. Manipulating them to our advantage could be a primary means of our species’ own survival.

At the time of this writing, there are scientists throughout the five continents that are regularly digging up evidence for the beneficial symbiotic relationships that exist among microbes and crops such as corn, cotton, tomato and peppers, even varieties that have been genetically modified. Plants typically give off a liquids rich in carbon, providing sustenance for the microbes. Some of these liquids are the result of the plants responding to environmental stressors such as attacks from insects, another rising concern as we are seeing an increase in invasive insect species. Other chemicals are produced due to increases in water following a deluge. The soil bacteria are sensitive to these chemical messages, and they then secrete chemicals of their own which can strengthen the already complex defenses of the plants.

As an example, there are studies done that have shown the right combination of beneficial microbes exposed to the seeds directly can be as effective as commercial pesticides against one particular type of worm known as the rice leaf-folder, which will wraps itself inside and then eat away the leaves of younger plants. Other studies have demonstrated that there are soil microbes that will significantly increase the overall growth and yields of important crops. One study from Germany, observed the same field over a 10-year period, learning that beneficial microbes have increased the rate of growth in maize plants but also boosted the prevalence of phosphorous as well as other elements that are critical to the growth of crops in the soil. In Colombia, where the effects of famine due to climate change are already being experienced, microbiologists have begun to mass-produce bacteria to colonize cassava plants, an economic staple. The result was an increase in the yields of cassava by 20 percent.

There are a number of farmers across the globe who strive to adapt to climate change, a sensitive issue as many established farms, both family and commercial, were plotted based on their precise ability for growing crops. As warming trends advance, dry areas are projected to become drier, and wet areas wetter. Those who have been hit hardest are small-scale farmers who grow their own crops with limited resources. A simple increase in their yield may benefit them economically as boosted crop sales generate cash and higher yields also allow them room to grow other crops. A study conducted using GMO cotton in India over a ten year period, ending in 2013, showed improved nutrition in the diets of subsistence farmers who grew the cotton for this reason – that they could grow more vegetables for themselves, while those who continued growing standard crops ate a diet primarily consisting of cereal. Additional revenue from the crops may then be invested in a wide array of “climate-smart” farming efforts geared towards the further conservation of water and soil.

There’s more good news, however, as to how these microbes may help guard against droughts. Some new studies have shown that microbes have a direct role to play in helping soil bacteria shield crops from harsh dry seasons while also improving their growth and ability to absorb nutrients from rapidly drying soil. If the crops are beneficial to the bacteria, they may help them adapt to extreme highs and lows as well as massive flooding events.

In one such study, the scientists observed that pepper plants cultivated within arid desert-like conditions can function as “resource islands” wherein they attract and manage to trap in any bacteria that sustain plant development during the periods when water is scarce. At present, we know that our bodies are dependent in many ways on microbes as well, which aid in processes like digestion, and may even control traits that we once attributed to genetics, such as body weight. Perhaps, this relationship with plants is not all that different. There was another study which identified soil bacteria that can actually signal the plants to temporarily open and shut the water absorbing pores on their leaves. Not only does this guard against fungi and other bacteria that may cause disease, but it can also keep the moisture trapped inside the plant.

So what’s the best way to go about cultivating this new biotechnology? Particularly at a time when many people believe GMO’s themselves to be harmful.

As we speak, companies involved in the production of foods and medicine, such as Nozozymes, Monsanto and Bayer Crop Sciences, are already launching their own investigation in to how we may go about the commercialization of soil bacteria. In their stead, are also several start-up companies that work tirelessly around the clock in order to commercialize microbial cocktails for growing food, but in all, we are only at the dawn of what may be an exciting new era of realizing the full potential that microbes have to offer.

The United Nations has officially designated 2015 as its International Year of Soil, part of a systematic plan to focus on not only climate change, but one of the problems it brings along with it – the issue of world hunger. Therefore, governments, funders and researchers of all stripes have been taking a serious look into the function of healthy soil in helping the United Nations reach its goal of achieving food security, while the population continues to climb past the seven billion mark, and the prolonged droughts of climate change continue to lower the yields of important food crops. While these initiatives often do a good job looking at the big picture, considering the potential that crop surpluses will have on communities and farmers, one thing that is so often overlooked is hidden in the soil itself, many species of which have evolved over the last six thousand years with their crops, part of a functioning ecosystem in which the crops themselves are essential to the life processes of the soil microbes.

At the end of the day, however, the use of soil microbes for producing better harvests may just be a single phase out of a trying and complex journey as we continue to improve the quality of our food. Even maintaining the quality of the natural resources may be a continuous battle, with climate change expected to worsen by the mid-21st century. Already there are efforts underway to cultivate new GMO’s capable of thriving in drier climates, extracted from beans.

As the climate is changing and unnatural changes like a continuous increase of CO2 continues to build up, risking the destruction of countless natural sanctuaries such as the Amazon River basin, now one of the most important climate sinks on the map, perhaps our best hope in offsetting the impending devastation may lie within nature itself – harvesting what the Earth already offers, in order to preserve our planet for the future.

James Sullivan
James Sullivan is the assistant editor of Brain World Magazine and a contributor to Truth Is Cool and OMNI Reboot. He can usually be found on TVTropes or RationalWiki when not exploiting life and science stories for another blog article.

How Saccharine Can Change Your Gut Bacteria

What do you put in your coffee – sugar or sweetener? It’s a question that probably most people avoid, and even fewer people who know the difference between each type of sweetener – natural or artificial. Most would be tempted with the latter – getting the sweetness while dodging the calories. Before we know it, we’re consuming vast quantities of aspartame, sucralose and saccharin, things that many have suspected have an impact on our long term health. However, science has only been able to find slight hints of negative consequences but a new study may have you rethinking things.

A team of Israeli scientists conducted a study last year suggesting that the continuous consumption of artificial sweeteners may be involved in a number of health problems — obesity and the long term health issues associated with it such as diabetes. While the study consisted of animal test subjects – in this case, mice, it also found a convincing cause of the problem – that artificial sweeteners alter the populations of intestinal bacteria used for directing bacteria, this indicates that humans could be at risk too.

A surprising but well established fact is that people, just like mice, acquire their ability for digesting and harvesting nutrient energy from food with the help of not only genetic makeup but from by the continuous activity of trillions of microbes living inside our digestive tract; a collective group known as the gut microbiome. The new Israeli study implies that these artificial sweeteners actually have an enhancing effect on certain populations of gut bacteria – the ones that draw energy supplements out of food and then convert it into fats for storage.

In this experiment, 10-week-old mice were administered daily doses of either aspartame, sucralose or saccharin. An additional cluster of mice served as a control group, fed on water laced with either glucose or sucrose. When 11 weeks elapsed, the mice given the sugar did well compared to their counterparts on the artificial sweeteners. The latter group showed abnormally high blood sugar (glucose) levels, which shows that their tissues experienced difficulty absorbing glucose from the blood. This state, known as “glucose intolerance” can bring about a number of health issues, such as diabetes and an increased risk for liver and heart disease. The condition is reversible, however. The mice were then given broad-spectrum antibiotics to eliminate their gut bacteria colonies entirely. Shortly after, the microbial population reverted to its initial makeup and balance, and along with it the blood glucose control.

“These bacteria are not agnostic to artificial sweeteners,” says computational biologist Eran Segal of the Weizmann Institute of Science in Rehovot, Israel, one of the study’s two lead scientists. The real surprise, however, is that microbial populations who did the best with artificial sweeteners were identical to bacteria colonies found in the stomachs of genetically obese mice.

Jeffrey Gordon, who is a physician and biologist at Washington University in St. Louis, has conducted research supporting that this relationship among bacteria and obesity is more than just coincidental. Over 90 percent of gut bacteria is derived from one of come two subgroups — Bacteroidetes and Firmicutes. Gordon discovered years ago that those mice who have genes triggering obesity contained 50 percent less Bacteroidetes related bacteria and 50 percent more of the Firmicutes strain than was found in normal mice. Transmitting the Firmicutes into normal mice (who produced the appetite limiting gene leptin), saw them becoming obese.

Perhaps this bacterial phenomenon happens in people too. Gordon later learned that populations of Bacteroidetes increase and Firmicutes bacteria decreases, when obese patients went through diets to lose weight. So do artificial sweeteners really make us sick? At least in a few cases, it’s somewhat likely, according to Segal.

For one phase of his study, Segal’s team analyzed a database consisting of 381 men and women. They learned that the patients who used artificial sweeteners on a regular basis were in fact much more likely to be overweight than those who did not. The comparison didn’t stop there though. These patients also had a higher likelihood of impaired glucose tolerance. Obesity itself is a risk factor for this impaired tolerance, a condition that can later lead to diabetes if not kept in check.

The pattern is there, but it does not necessarily show that sweeteners caused the problems on their own. Its possible that people already obese are just more apt to eating more artificial sweeteners than most people. So Segal’s team took things a step further, where they analyzed the correlation as it affected a small group of lean and healthy human volunteers – people that typically abstained from artificial sweeteners. They were then given the maximum dose recommended by the U.S. Food and Drug Administration for an interval of five days. Afterwards four out of seven subjects exhibited a reduced glucose response in connection to the abrupt shift in their gut microbes. As for the other three volunteers whose overall glucose tolerance did not show declines, neither did their levels of gut microbes.

Not everyone seems to be vulnerable to the effect, but the study is an ambitious one that’s left a bit to consider. The Israeli group’s conclusion, from their paper, suggests that “artificial sweeteners may have directly contributed to enhancing the exact epidemic that they themselves were intended to fight” – causing many people to become overweight and sick from the complications that often result from excessive consumption of sugar.

There may be a cause-and-effect chain revealing a pattern from sweeteners to microbes to obesity that may reveal some questions about human obesity, said New York University’s gastroenterologist Ilseung Cho, whose field of expertise is the function gut bacteria play in human disorders. Often when people go from sugar to low-calorie sweeteners, they do it to lose weight, and often fail to lose it in the way they expect to. “We’ve suspected for years that changes in gut bacteria may play some role in obesity,” he says, but distinguishing the effect has been difficult. “Whatever your normal diet is can have a huge impact on the bacterial population of your gut, an impact that is hard to overestimate. We know that we don’t see the weight-loss benefit one would expect from these nonnutritive sweeteners, and a shift in the balance of gut bacteria may well be the reason, especially a shift that results in a change in hormonal balances. A hormone is like a force multiplier—and if a change in our gut microbes has an impact on hormones that control eating, well, that would explain a lot,” said Cho.

As with any good study, there is a host of questions left to be answered. Cathryn Nagler, who is a pathologist at the University of Chicago and an expert on gut bacteria and food allergies, said that the degree of human genetic variations may bring the practice of testing mice into further questioning. “Still, I found the data very compelling,” she said regarding the artificial sweetener study which she was not a part of. Relman has agreed that rodent studies do not always best reflect the same changes in humans. “Animal studies can point to a general phenomenon, but animals in these studies tend to be genetically identical, while in humans, lifestyle histories and genetic differences can play a very powerful role,” he said. The microbial collection within the body though reveals quite a long road map of both genetic and environmental patterns of behavior.

“The microbiome is a component intertwined in a complex puzzle,” Relman added. “And sometimes the genetics is so strong that it will override and drive back the microbiota.” Genetic variation may be the reason that only four out of the seven people who were given saccharin showed changes in their levels of gut bacteria. Genetics however, is only one out of a myriad of possible factors. Should someone have a genetic predisposition to obesity and then consume a regimen of foods that cause obesity, these microbes may be able to use such a diet to their own advantage, thereby amplifying their impact.

The Israeli researchers have yet to determine whether there is sufficient evidence that effectively links artificial sweeteners to metabolic disorders, however, along with other scientists, they are thoroughly convinced that the presence of saccharine has a significant effect on the stability of the digestive microbes our stomachs depend on. “The evidence is very compelling,” said Turnbaugh. “Something is definitely going on.” Segal has already switched to natural sweeteners only for his coffee.

James Sullivan
James Sullivan is the assistant editor of Brain World Magazine and a contributor to Truth Is Cool and OMNI Reboot. He can usually be found on TVTropes or RationalWiki when not exploiting life and science stories for another blog article.