Firebugs survive by harvesting nutrients from their gut flora

(NaturalNews) Genetics are not a onetime deal, handed down through birth. Fate doesn't rest on genes alone. Nature is more interconnected than that; gene expression is influenced by proteins, enzymes, and bacterial hosts. Larger organisms are directly impacted by invisible hosts, the bacteria living inside. In fact, new research from the Max Planck Institute for Chemical Ecology and Friedrich Schiller University in Jena, Germany shows that bacteria living inside the stomach of the firebug play an important role in the insect's survival, influencing their genetic makeup, metabolic stability, and utilization of vitamins. In fact, the bacteria live in symbiosis with the bugs, aiding in digestion of food, and detoxification of parasites, while providing essential nutrients that the insects don't obtain from their diet. The family of bacteria responsible in this symbiotic relationship is from the Coriobacteriacea family.

Symbiotic relationship with bacteria ensures firebugs survival

The researchers found that the European firebug Pyrrhocoris apterus and the African cotton stainer Dysdercus fasciatus have a difficult time finding essential B vitamins in their diet, which consists mainly of plant seeds. The researchers found that bacteria living in the insect's guts are responsible for producing the necessary B vitamins to stabilize their metabolism. This also influences the regulation of the insects' genes.

To access the B vitamins from the bacteria, the firebugs must first burst the cell walls of the bacteria host. The firebugs perform this action using specific enzymes. The dead bacteria cells release vitamins to the firebugs. Without breaking the bacteria down and accessing the surplus of B vitamin synthesis, the firebugs are unable to live and reproduce. Firebugs that don't have a healthy relationship with the Coriobacteriaceae family have higher mortality rates and are less fertile across the board. This was observed in controlled experiments: without the B vitamins, obtained from either microbes or artificial sources, firebugs died more readily in their juvenile stages of life.

Study author Hassan Salem spoke on the importance of the symbiotic relationship, "As a condition of nutrient limitation, firebugs that lack their symbionts were found to exhibit a different metabolic profile; one that can be restored either through the artificial supply of B-vitamins into their diet, or by reintroducing the insect to its symbionts."

The bug's survival comes down to vitamin assimilation

"Vitamin supplementation is probably too friendly of a word," says Hassan Salem. "Surrendered is somewhat more accurate, given how the host is thought to extract the vitamins from its microbes, it basically exploits the microbes to gain the benefits. Still, since only a fraction of the symbiont population is harvested, the microbes likely benefit from the association with the host by gaining nutrition in the bug's gut and a secured transmission route to the next generation."

When the researchers studied the absence of microbes in the firebug's gut, they also observed various genetic changes. Without the microbes, the insect's genes change, increasing activation enzymes and B vitamin transporters. If the insects do not obtain enough B vitamins from their diet, their genes change, expressing proteins that are responsible for transporting B vitamins across the gut epithelium and into cells. These genetic changes cause the cells to move into action, absorbing remaining vitamins from the gut. The gene's expression shows encoding for special antimicrobial peptides, like lysozyme, indicating the change. When the microbes are present and are providing the B vitamins, the expression of the genes in the insect's stomach are normal.

This begs the questions: how important are the microbes living in the human gut for normal genetic expression? How dangerous are antibiotics for disrupting the balance of healthy bacteria in the gut and how might these drugs change genetic expression in humans?

Sources :

http://www.mpg.de