Science Square

  • Issue 94 / July - August 2013



    Science Square

    The Fountain

    Gettıng Help from Cows to Treat Human Dıseases
    Humans have been raising cows for their meat and milk for thousands of years. A new study suggests that our humble friends have even more to offer than basic sustenance. Researchers claim that cow antibodies may help us to treat deadly infections. Antibodies are large proteins produced by our immune systems to identify and neutralize foreign substances such as a bacteria, viruses, and parasites. Antibodies are “Y” shaped molecules, built of a tail and two identical arms. The arms are used to grab specific targets called antigens. At the very end of these arms, there is a small set of protein loops called complementarity-determining regions or CDRs. By a rearrangement of the genes that code CDRs, a vast and diverse population of antibodies are generated in organisms to bind to any foreign invaders. An antibody’s specific target is determined in CDR H3, which is a sub region of CDR. Studies previously suggested that antibodies with longer CDR H3 regions might work in viral infections much more effectively. Long CDR H3s are unfortunately rare in humans. Interestingly, cows make antibodies with very long CDR H3 regions. Genetic and X-ray crystallographic analyses showed that cow antibodies consist of a long stalk topped with an antigen-binding knob, which contains an unusually high level of the sulfur-containing amino acid cysteine. These cysteine-residues are thought to make a variety of mini loop structures by binding themselves to different protein stretches of the CDR regions. Therefore, cow antibodies act like probes on a thin extended scaffold, which can fit into narrow crevices to reach and bind to unique antigenic pathogens that normal antibodies simply cannot reach. Of course, now everyone asks, “Why does the cow immune system needs to make such antibodies?” One explanation is that a cow’s unusual, giant, grass-fermenting stomach contains an extensive collection of bacteria and viruses, and this could be the only efficient way to create a defense from such pathogens. The power of long CDR H3 antibodies has a wide variety of human and veterinary applications. Researchers plan to take the first step by immunizing cows with HIV antigens to see if recovered antibodies with elongated CDR H3 are able to neutralize the AIDS-causing viruses. After a potentially successful series of experiments, this new antibody system is expected to be applied towards other infectious diseases.

    Cellular Renewal and Omega Fatty Acıds
    A cell can be very economical under stressful conditions. One of the major stress factors for a cell is the lack of nutrients. During starvation, a cell relies on its internal reserves of energy; in other words, the cell recycles. One main mechanism of how a cell adapts and survives in the absence of an external energy source is autophagy, which is a destruction of the cells own components for cell survival. Enhanced autophagy may lead to improved clearance of old or damaged cellular components. It has also been suggested that autophagy can extend a cell’s lifespan by maintaining cellular function. In addition, defects in autophagy function are implicated in a variety of human diseases such as Parkinson’s disease, cancer, and metabolic syndromes. However, the activator metabolites of the autophagy process are still largely unknown. A recent study from Massachusetts General Hospital sheds light onto the metabolites that regulate the adaptation of the cell during starvation. Using the nematode worm, Caenorhabditis elegans, researchers demonstrated that the polyunsaturated fats (PUFAs) found in fish oils, omega 3/6, are increased during starving conditions. The increased levels of the omega-6 PUFAs allowed the worm to resist starvation via inducing autophagy. Researchers later tested these metabolites on human cells and observed almost identical results. Autophagy allows not only for excess cell components to be used as internal energy sources, but also for the protection of the organelles from destruction due to starvation, therefore leading to the survival of the cells. Hence, this study shows a potential link between PUFAs that are enriched in fish oils, and increased survival and longevity of cells.

    Why Women Remember Faces Better
    Why can some people remember faces much more easily while others quickly forget someone they’ve just met? A new study might answer this long-standing question. In this study, researchers showed study participants randomly selected faces on a computer screen. By using eye tracking technology, they monitored where, and for how long, participants looked at the faces. Each face was assigned a name that participants were asked to remember over a period of one day and four days. As many people predicted from their social experiences, women were found to remember the faces much better than men. When eye tracking records were analyzed, women were found to fixate on the facial features far more than men. This was completely outside of women’s awareness, as individuals usually don’t notice where their eyes fixate. This study shows a new gender-specific mechanism for episodic memory formation and consolidation. In real life, women might unconsciously look more at the new faces then men, thereby creating richer, superior memories. These results also open up a new possibility for the treatment of people with memory impairments by simply enhancing the eye movement patterns and scanning times.

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