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Science Square (Issue 112)
Jul 1, 2016

A new meaning to the term “bird brain”

Olkowicz S. et al. Birds have primate-like numbers of neurons in the forebrain. Proceedings of the National Academy of Sciences of the United States. June, 2016.

Calling someone a “bird brain” is no longer an accurate insult to their intelligence. Although birds generally have small brains, a recent study showed that certain types of birds, such as parrots, songbirds, and ravens, have a surprisingly high number of neurons, the brain cells responsible for processing power, in their small brains. Researchers dissected 73 brains from 28 bird species, then dissolved them completely in a detergent solution. Once they obtained a homogenous solution of brain cells, they labeled and counted them to calculate the exact number of neurons in each part of the brain. They particularly focused on the forebrain region called the pallium, a structure of the bird brain that is analogous to the mammalian cerebral cortex. Their analyses revealed that neuronal sizes in bird brains were much smaller than expected, they displayed shorter but more compact connections between neurons, and in some birds, the pallium contained twice as many neurons, compared to primate brains of similar sizes. Scientists have always been puzzled that birds can be very smart yet have very small brains. For example, ravens are very intelligent, capable of using tools, planning ahead, and solving complex problems. While a direct link between number of neurons and cognitive ability has not been established, this study provides an explanation for the remarkably high cognitive power of some birds.

Bacteria as vaccine vessels

Li Y. et al. In situ pneumococcal vaccine production and delivery through a hybrid biological-biomaterial vector. Science Advances. July, 2016

The thought of ingesting Escherichia coli (E. coli) bacteria is probably not appealing to most of us, but what if it can be used to treat diseases?  E.coli is a rod-shaped bacterium that normally lives in the intestines of people and animals. Most E. coli strains are harmless, and are actually important for a healthy human intestinal tract. Researchers developed an E.-coli-based transport capsule to increase the effectiveness and efficiency of the next generation of vaccines. The capsule is  generated by wrapping the positively charged synthetic polymer beta amino ester around the negatively charged bacteria. Then, researches inserted a known protein-based vaccine against pneumococcal disease into the capsule and tested the effects in mice. Analyses of vaccinated mice showed that the capsule caused an enhanced immune response by activating both the passive and active targeting of immune cells. Moreover, those mice who had been administered the capsule exhibited strong vaccination capabilities against pneumococcal disease. The E-coli-based capsule is relatively cheap and flexible, and can be used in a variety of therapies in the future, including fighting cancer and other infectious diseases.

Paper-based microbial fuel generates power without current consumption

Hashemi N. et al. A paper-based microbial fuel cell operating under continuous flow condition. Technology. June, 2016.

Researchers demonstrated a three-dimensional paper-based microbial fuel cell (MFC) that exploits capillary action to channelize the liquids through the MFC system without using an external power.  The system was able to run for five days and generate current, as biofilm forms on the anode. The mini eco-friendly MFC generates 1.3 μW of power and 52.25 μA with a power density of approximately 25 W/m3. These results show that the paper-based microbial fuel cells could be the next alternative power source, by transforming chemical energy into electrical energy without the use of any outside power. The key element of the project is the size and thickness of the biofilm. Bacterial cells metabolize electron-rich substances in a complex process involving many enzyme-catalyzed reactions and ultimately generate free mobile electrons. Then electrons are free to travel to the anode through one of many modes of electron transport. This device, for the first time, demonstrates that microbial fuel cells can be used for longer durations and operate individually. The research team is currently exploring new improvements in the system to better control the voltage output and to create a constant current. Although the current MFC model is not ready for commercialization yet, it opens new avenues in applications for biosensors and power generation.