Graphic by Maia Brown


This month, researchers showed that people like coffee and beer not because of their taste, but because of how bitter beverages make people feel. Northwestern professors found how methane-utilizing bacteria can transform the harmful greenhouse gas methane to the usable fuel methanol. Scientists also discovered that the special design of vaccines with a certain chemical structure improved animals’ overall survival from cancer.

The reason you love coffee and beer

Have you ever wondered why you can’t get enough of coffee or beer whereas your friends prefer orange juice and soda? Northwestern researchers found that this preference for bitter or sweet beverages is not a result of personal taste. Instead, it is the genes related to the psychoactive properties of these beverages that are affecting your taste preferences. That is, the way drinks make you feel affects how you perceive beer compared to coke, not the taste per se.

Feinberg Professor Marilyn Cornelis and her research team found a link between genetics and beverage consumption. It is common sense that having too many alcoholic drinks or taking in too much sugar and caffeine can result in poor health conditions. By understanding why people have different taste preferences, researchers wanted to know the obstacles and find out ways to intervene in people’s diets.

Professor Cornelis and her team categorized beverages into two groups: a bitter-tasting group (coffee, tea, grapefruit juice, beer, red wine and liquor) and a sweet-tasting group (sugar-sweetened beverages, artificially sweetened beverages and non-grapefruit juices). Scientists collected bitter or sweet beverage intake data over 24-hour periods from about 336,000 individuals in the U.K. Then they studied their genes to see whether there exists a link between their genes and beverage preferences.

The result showed that the genetic factor that affects an individual’s response to caffeine or alcohol can result in a person’s love for coffee and beer. For example, if coffee makes you feel energetic or beer makes you happy and cozy, you have a positive response to the psychoactive properties in bitter beverages. This explains your preference for bitter drinks. You don’t necessarily need to love the taste of bitter coffee or beer — you might just like how bitter drinks make you feel. Researchers also found that people with a variant in a gene, called FTO, usually prefer sweet beverages like Coca-Cola. But this finding seems counterintuitive because the same FTO gene also relates to low risk of obesity. Although the FTO gene variant is linked to low obesity risk, over-consuming sweet beverages will eventually lead to weight gaining and other health problems.

A new way to combat climate change by reducing greenhouse gas and producing sustainable fuel at the same time

Previous research has shown that the greenhouse gas methane can convert into liquid methanol, a readily usable fuel, using methanotrophic (methane-utilizing) bacteria as the catalyst. However, until now, it is not clear how the bacteria make this reaction happen. Although methane can be used directly as fuel, liquid methanol is easier to transport and store. Northwestern professors Amy C. Rosenzweig and Brian M. Hoffman lead a team to find out how these bacteria actually catalyze the reaction. Their findings may provide a new method to reduce the potent greenhouse gas and produce sustainable fuel.

The study showed that these methane-utilizing bacteria catalyze the conversion from methane to methanol at a monocopper site, a site that contains only one copper ion. This was an encouraging discovery, as scientists had been wondering for decades about the identity and the structure of the metal ions that catalyze this useful reaction of transforming a greenhouse gas to sustainable fuel. Methane is an important greenhouse gas that is abundant on Earth, making it a major force for global warming and good material for fuel. Yet, converting methane to liquid methanol is extremely difficult. Under the current industrial process, this conversion requires tremendous pressure and high temperature, reaching higher than 1,300 degrees Celsius. But using this methanotrophic bacteria, this same reaction can happen at room temperature.

Scientists are working on to further understand how these bacteria catalyze the reaction under room temperature. It is possible that in the future researchers can design a human-made catalyst that can carry out the methane-to-methanol reaction with the same simple process. This approach may provide a new way to combat climate change by eliminating excess greenhouse gas and producing sustainable fuel at the same time.

Structure matters for vaccines that stimulate anti-cancer immune responses

In the design of vaccines, a tiny change in the structure of a component can result in completely different results in vaccine effectivity. A Northwestern research team investigated the potential structures of spherical nucleic acids (SNAs) in vaccines that aim to stimulate the patient’s immune system to find and attack tumors.

SNAs are synthetic globular — rather than linear — forms of DNA and RNA. SNAs are arranged in a spherical geometry, so it is actually three-dimensional. This means that they are small enough (roughly 50 nanometers in diameter) to enter immune cells and boost immune responses to cancer. However, until now, scientists did not know which structure of SNAs is the most effective in stimulating the immune response. Co-led by Weinberg Professor Chad A. Mirkin, Feinberg Professor Bin Zhang and McCormick Professor Andrew Lee, the team experimented different structures of SNAs with same components.

All SNAs vaccines have an antigen, a substance that is recognized and targeted by an immune response, and an adjuvant, a substance that enhances the body’s immune response to the antigen. Researchers deliberately changed the positions of the antigen, making it either housed in the core of the SNA, interspersed with the adjuvant or attached to the adjuvant. After testing these structurally different vaccines on animals, they found that the antigen interspersed with the adjuvant had the best result, which eliminated tumors in 30% of animals tested, improved their overall survival from cancer and prevented tumors from reemerging. Changes in the structure directly influence how the immune system recognizes the vaccines, and therefore affect how effective those different vaccines are.

Northwestern researchers are optimistic that by further improving the design of vaccines, scientists can produce better medical responses for many types of cancer and other diseases and eventually use them in clinical trials.