There’s an “Ome” for That

In the 13 years since the sequencing of the human genome, the list of “omes” has proliferated. Drop us a comment with your favorite ome—we may feature it in a follow-up post next month.

Have you ever collected coins, cards, toy trains, stuffed animals? Did you feel the need to complete the set? If so, then you may be a completist. A completist will go to great lengths to acquire a complete set of something.

Scientists can also be completists who are inspired to identify and catalog every object in a particular field to further our understanding of it. For example, a comprehensive parts list of the human body—and of other organisms that are important in biomedical research—could aid in the development of novel treatments for diseases in the same way that a parts list for a car enables auto mechanics to build or repair a vehicle.

More than 15 years ago, scientists figured out how to catalog every gene in the human body. In the years since, rapid advances in technology and computational tools have allowed researchers to begin to categorize numerous aspects of the biological world. There’s actually a special way to name these collections: Add “ome” to the end of the class of objects being compiled. So, the complete set of genes in the body is called the “genome,” and the complete set of proteins is called the “proteome.”

Below are three -omes that NIH-funded scientists work with to understand human health.

Genome

Illustration of the entire outer shell of the bacteriophage MS2. Credit: Wikimedia Commons, Naranson.

The genome is the original -ome. In 1976, Belgium scientists identified all 3,569 DNA bases—the As, Cs, Gs and Ts that make up DNA’s code—in the genes of bacteriophage MS2, immortalizing this bacteria-infecting virus as possessing the first fully sequenced genome.

Over the next two decades, a small handful of additional genomes from other microorganisms followed. The first animal genome was completed in 1998. Just 5 years later, scientists identified all 3.2 billion DNA bases in the human genome, representing the work of more than 1,000 researchers from six countries over a period of 13 years. Continue reading

Sugar Rush in Research

Cookies
Sugar sprinkled on cookies and other treats is often an attractive—and sweet tasting—finishing touch. But the sugar-rich coating that surrounds most cells is far more—it’s a vital ingredient for many basic cellular processes. Credit: Stock image.

Simple sugars such as sucrose (found in the sugar bowl) and fructose (in fruits and honey) provide the sweet finishing touches on many holiday treats. But did you know that versions of these molecules also serve important functions in our cells?

Cells assemble sugar molecules into chains known as glycans. These glycans, which can be linear or branching, play an astounding number of biological roles. When bound to proteins called lectins, they enable a fertilized egg to attach properly onto a woman’s uterine wall and help immune cells move out of a blood vessel to the site of an infection. When decorated with specific patterns of molecules called sulfates, glycans can help direct the growth of nerves. And it’s the glycans found on our blood cells that define blood type (A, B, AB or O). Continue reading

The Sweet Side of Chemistry

Glycans
Simple sugars connect in long, branched structures to create glycans. Credit: Stock image.

We’re in the middle of National Chemistry Week Exit icon, which this year focuses on “The Sweet Side of Chemistry—Candy.” Studying sugar chemistry is also relevant to our health.

The sugar in chocolate, taffy and other confections is a type of simple sugar called sucrose. In our bodies, sugars can exist in many forms, ranging from individual units like glucose to long, branched chains known as glycans containing thousands of individual sugar units linked together.

Glycans are involved in just about every aspect of how our cells work. They help make sure proteins are folded into the proper shape so they function correctly. They act as ZIP codes that direct newly made proteins to the right cellular locations. Some divert white blood cells to infection sites, and others serve as anchors for viruses to latch onto.

Because of the diverse and critical roles that glycans play in our bodies, chemists want to learn more about these molecules, with a long-term goal of harnessing them to treat or prevent disease. Read about some of their discoveries in the Why Sugars Might Surprise You article from Inside Life Science and the Life is Sweet article from Findings magazine. The You Are What You Eat chapter from ChemHealthWeb offers more details about the chemistry of sugar.

Carbohydrates as Bacterial Camouflage: How Our Immune System Responds

bacteria
Although invisible to our immune system’s antibodies, strains of a pneumonia-causing bacteria, Pseudomonas aeruginosa (orange), are easily detected by galectins. Credit: Centers for Disease Control and Prevention.

When harmful strains of bacteria invade our bodies, our immune system produces antibodies that identify the intruders by the specific carbohydrate structures coating them. Some strains, however, have coatings that mimic the carbohydrate structures found on our own cells, and this disguise allows them to evade detection by antibodies.

A team of scientists led by Richard Cummings of Emory University found that galectins, a class of proteins naturally produced by our bodies, can identify and kill these concealed bacteria without damaging our own mimicked cells. To make this discovery, the team used glass slides covered with more than 300 different carbohydrates extracted from the surface of bacterial cells. After testing the ability of galectins and antibodies to bind to specific carbohydrates on these slides, the researchers observed that the galectins easily detected the mammalian-like carbohydrates that the antibodies failed to recognize.

These findings provide a clearer understanding of the complementary roles played by galectins and antibodies in protecting us from a broad range of infections.

This work also was funded by NIH’s National Institute of Allergy and Infectious Diseases and National Heart, Lung, and Blood Institute.

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