Of all the molecules in organisms, only a fraction have structures and functions that are known. New research led by Prof. Frank Schroeder, chemistry and chemical biology, has determined a series of molecules used in a chemical “language” between worms that could have repercussions for our understanding of human biology.
“In the past 30 years, biology has advanced tremendously because of genetic sequencing; on the other hand, characterization of small molecules has lagged behind,” Schroeder said.
He published the report in last month’s issue of PLoS Biology.
He found that there is a significant knowledge gap since many of the smaller molecules synthesized in the bodies of animals are of unknown structure and function. Schroeder’s lab has discovered the structure and function of more than 200 small molecules in C. elegans, the species of worm used in his experiments.
The worm “language” that Schroeder studies is derived from chemical signals that are made from the same basic biological building blocks, such as sugars, lipids or amino acids, that make up all life forms. Schroeder said these building blocks are placed into different combinations by the worm in order to send specific messages. This technique mirrors how people make words out of different combinations of letters in specific orders, he said.
“Worms take an amino acid, a sugar, a lipid and sometimes a nucleotide and combine these things in a selective way in order to send a chemical message,” Schroeder said. “These messages can tell other worms to go into hibernation, to run away or to come together, or to indicate nearby food quality.”
While this chemical language can signal messages to other worms, it can also be used to communicate messages between different parts of the same worm. Although the chemicals the worms use to communicate to one another are not found in higher organisms, chemicals that a worm uses to communicate between its different tissues are likely replicated in mammals and humans, according to Schroeder. Understanding this type of communication in worms will aid in understanding the biology and physiology of humans, he said.
“We are only just learning to break into their code,” Schroeder said. “And we are interested in seeing if similar compounds exist in higher organisms because the worm’s chemical signals are made up of building blocks available to any organism.”
He said that variants of the enzymes that make these compounds are present in higher organisms including humans, and that these enzymes are most likely used for communication between different tissues in the body.
“The moment when the organism decides to attach different building blocks to each other in specific ways allows it to produce coherent signals for communication,” said Stephan von Reuss, a postdoc in Schroeder’s lab. Finding out how the worms create these chemical signals and where they originate from in the body will help determine if the signals can be found in higher organisms, von Reuss said.
The roundworm C. elegans is used in these experiments because it is considered a model organism.
“The worms are perfect to study because their genome is fully sequenced, they have a set life cycle of about two to three weeks and many of their metabolic pathways are conserved in higher organisms,” Yevgeniy Izrayelit grad said.
Schroeder also said that C. elegans, as tiny worms, are much easier to take care of than mammals. “It is difficult for a chemistry lab to keep hundreds of thousands of mice, but we can have millions of worms,” Schroeder said. This allows his lab to examine the pathways of many different worms over a short period of time.
Roundworms such as C. elegans are not only important to study because they represent simple organisms that share biological functions with higher animals, but they also affect world health. “More than half of the world’s population is infected with parasitic nematodes [roundworms], especially in third world countries,” Schroeder said. These parasites, although normally not lethal, can cause discomfort in their hosts.
The next step in the research is to discover to what level these biochemical pathways are conserved in higher organisms. Schroeder also hopes that his research “will eventually lead to developments in medicine relating to nematodal infections.”
Original Author: Sarah Cohen