Author Archives: Anna Hargrave

Social interactions and the microbiome

The microbiome, or the collection of bacteria living inside humans and other organisms, is an important topic in research today, because many scientists have made connections between different diseases and illness to the populations of bacteria inside us, specifically in our guts. Previously, ZME Science has covered what the microbiome is  and several important studies.

There are still many questions about the microbiome, because diet, genetics, location, and lifestyle all play a role in what species are dominant or absent and how well they grow inside us. Performing studies outside a lab is particularly difficult since it is hard to isolate one of those factors and study how the populations change.

Image via Amboseli Baboons.

Dr. Jenny Tung and her research team examined the microbiome and how a social network affected the populations of bacteria of Amboseli baboons of Kenya. Previously, these baboons were studied in their natural habitat, and observed for extended period of time by a different research group. There were a total of 48 baboons that naturally existed in two different groups, Mica’s group and Viola’s group. The baboons in each group groom each other, and how frequently this behavior was observed and between which pair was documented for a year. For an entire month, feces samples were collected from each animal. From these samples, shotgun metagenomic sequencing was applied, and this method cleaves the genetic material found in the sample and sequences the fragments. The fragments tell researchers what kind of bacteria there is and what kind of chemical processes are happening.

The authors state:

“Our results argue that social interactions are an important determinant of gut microbiome composition in natural animal populations – a relationship with important ramifications for understanding how social relationships influence health, as well as the evolution of group living.”

They found that social group was more important to predicting the species of bacteria than sex or age. Since Mica and Violas’s group lived in the same habitat and their diets were essentially the same, these factors could not explain why the microbiomes were different.

They also found that the baboons in the same group that groomed each other more frequently had more similar microbiomes, both in terms of what species of bacteria are present and how large the population is. A potential explanation for this is that this pair of baboons ate more similarly than the rest of the group. This potential explanation was taken into account using statistical tests, but these statistical tests ultimately did not produce any results that suggested the microbiome composition changes were due to grooming partner’s diets.

Though this study represents important new findings for the microbiome, we still do not understand how this works. Researching more about how the social network changes the populations of microbes inside us could help us understand both evolution and disease better.[1]


[1] Tung, Jenny, Luis B Barreiro, Michael B Burns, Jean-Christophe Grenier, Josh Lynch, Laura E Grieneisen, Jeanne Altmann, Susan C Alberts, Ran Blekhman, and Elizabeth A Archie. “Social Networks Predict Gut Microbiome Composition in Wild Baboons.” ELife (2015). Web. 15 June 2015.


bacteria stock photo

Engineering microorganisms for future generations

Engineering microorganisms may be the key to solving major environmental problems, particularly the accumulation of greenhouse gases and fossil fuel overconsumption.

bacteria stock photo

Image: Yale News

One type of microorganism that is particularly interesting is autotrophs because of their ability to “fix” carbon. This means that there is a chemical reaction converting carbon dioxide into an organic compound. To take advantage of the autotroph’s natural ability, two different approaches must be considered. One approach is enhancing the efficiency of the metabolic pathway inside the autotroph. This means that conditions, like pH, media, and temperature, are optimized so it becomes the most effective process as possible. The second approach is to isolate the genes that allow it to fix the carbon and transplant the genes into a new organism. This approach is more challenging, because both organisms and their parts must be studied in depth.

Researchers at Pennsylvania State University chose to use the second approach and engineered an organism that can convert carbon dioxide and simultaneously produce hydrocarbons to be processed into gasoline. This concept is very lucrative and eco-friendly if it could be applied on a large scale, because it would reduce the amount of carbon dioxide, a major greenhouse gas, and decrease our dependence on fossil fuels.

Their project isolated the gene known to produce hydrocarbons from Botryococcus braunii algae and inserted this gene into bacteria that has an autotrophic mode. Two types of bacteria, Rhodobacter capsulatus and Ralstonia eutrophia, were used in this project, and these specific species were chosen, because both have multiple metabolic pathways but different from each other physiologically and metabolically. The inserted algaeic gene ultimately generates long chains of carbons, and this is the starting material to make gasoline, kerosene, or diesel.

Botryococcus braunii. Image: Wikimedia Commons

Botryococcus braunii. Image: Wikimedia Commons

Currently, this project cannot be applied on a larger scale, because the energy, time, and money put into the project was greater than the value of the product yield. Further research must be conducted to optimize the microorganisms and their conditions. Overall, applying bioengineering to improve our environment is fascinating premise and shows a lot of potential for future generations.


Khan, Nymul E., John A. Myers, Amalie L. Tuerk, and Wayne R. Curtis. “A Process Economic Assessment of Hydrocarbon Biofuels Production Using Chemoautotrophic Organisms.” Bioresource Technology: 201-11. Web. 3 June 2015.

Nybo, S. Eric, Nymul Khan, Benjamin M. Woolston, and Wayne R. Curtis. “Metabolic Engineering in Chemolithoautotrophic Hosts for the Production of Fuels and Chemicals.” Metabolic Engineering. Web. 3 June 2015.