Firebugs depend on gut bacteria for vitamin supply. Scientists of the Max Planck Institute for Chemical Ecology in Jena, Germany, found that bacterial symbionts in the insects’ gut produce these vitamins and thereby ensure the host’s metabolic stability.
The vitamin supply provided by the symbionts directly influences the gene regulation of their host: If the bacterial associates are absent, the bugs show a characteristic vitamin deficiency response.
However, the symbiosis between the bugs and their bacteria is not necessarily a harmonious one: The insects are proposed to actively harvest the vitamins from the bacteria by using specific enzymes that burst open the bacterial cell walls.
Microbial partners are important for the nutrition of many insects. They help detoxify and digest food, but also provide essential nutrients that insects need in order to survive. The European firebug Pyrrhocoris apterus and the African cotton stainer Dysdercus fasciatus feed mainly on plant seeds that are poor sources of essential B vitamins.
Scientists of the Max Planck Research Group Insect Symbiosis at the Max Planck Institute for Chemical Ecology in Jena, Germany, together with colleagues at the Friedrich Schiller University, have now found that bacterial symbionts in the insects’ gut produce these vitamins and thereby ensure the host’s metabolic stability and, ultimately, survival.
Interestingly, the vitamin supply provided by the symbionts directly influences the gene regulation of their host: If the bacterial associates are absent, the bugs show a characteristic vitamin deficiency response. However, the symbiosis between the bugs and their bacteria is not necessarily a harmonious one: The insects are proposed to actively harvest the vitamins from the bacteria by using specific enzymes that burst open the bacterial cell walls. (Proceedings of the Royal Society B: Biological Sciences, November 2014).
In their quest for a balanced meal plan, firebugs – and many other animals – depend on dietary supplements. Firebugs are a group of terrestrial insects that includes the ubiquitously found European firebug Pyrrhocoris apterus as well as the agricultural pest, the African cotton stainer Dysdercus fasciatus. As demonstrated previously, firebugs depend on their gut microbes for successful development.
The symbiotic bacteria from the Coriobacteriaceae family provide essential vitamins. Microbe-free bugs suffer high mortality and produce fewer young than bugs that have their microbial partners (see our press release “Bugs need symbiotic bacteria to exploit plant seeds” - http://www.ice.mpg.de/ext/976.html , January 9, 2013).
Controlled experiments by the scientists from Jena implicate the bacterial symbionts in supplementing B vitamins to firebugs as an important feature of this association. Firebugs that lack their symbionts, but are reared on an artificial diet rich in B vitamins do perfectly fine compared to bugs that have their microbes. It is only when B vitamins are eliminated from the artificial diet that symbiont-free bugs are observed to suffer high mortality during their juvenile stages.
What is even more striking is the effect of symbiont absence on the host’s metabolism. “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,” Hassan Salem, the first author of the study explains. Profiling the expression patterns of host genes revealed that the insect significantly increases the abundance of B vitamin transporters and activation enzymes when reared in the absence of its gut microbes.
As the scientists found out, proteins that carry out the active transport of B vitamins across the gut epithelium and into cells are expressed in higher amounts when the host is lacking these important nutrients, as a means of increasing the efficiency in scraping the scarce vitamins together from the gut content. Supplementing B vitamins into the insect’s diet or reestablishing the symbiotic partnership restores normal expression patterns of those genes.
An examination into the host’s immune response to symbiont presence suggests that firebugs actively harvest their bacterial partners by lysing, or bursting open, the bacterial cells. This enables them to take up the free vitamins from the dead cells. The expression of genes encoding special antimicrobial peptides, specifically, lysozyme, supports this assumption.
“Vitamin supplementation is probably too friendly of a word. 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,” says Hassan Salem.
While strides have been made in our effort to understand the importance of the complex human microbiome, the exact functions of the majority of our gut associates remain unknown, as is their impact on our metabolism and overall physiology. As such, valuable insights can be gained from insects and their often simple and experimentally tractable microbial communities. [HS/MK/AO]
Salem H, Bauer E, Strauss A, Vogel H, Marz M, Kaltenpoth M. (2014) Vitamin supplementation by gut symbionts ensures metabolic homeostasis in an insect host. Proceedings of the Royal Society B: Biological Sciences. 281, 2014183
Dr. Martin Kaltenpoth, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany, Tel. +49 3641 57-1800, E-Mail email@example.com
Dr. Hassan Salem, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany, Tel. +49 3641 57-1804, E-Mail firstname.lastname@example.org
Angela Overmeyer M.A., Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07743 Jena, +49 3641 57-2110, email@example.com
Download of high resolution images via http://www.ice.mpg.de/ext/735.html
Angela Overmeyer | Max-Planck-Institut
How molecules teeter in a laser field
18.01.2019 | Forschungsverbund Berlin
Discovery of enhanced bone growth could lead to new treatments for osteoporosis
18.01.2019 | University of California - Los Angeles
The scientific and political community alike stress the importance of German Antarctic research
Joint Press Release from the BMBF and AWI
The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...
World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles
The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.
Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.
In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...
Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.
It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:
The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.
One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...
16.01.2019 | Event News
14.01.2019 | Event News
12.12.2018 | Event News
18.01.2019 | Materials Sciences
18.01.2019 | Life Sciences
18.01.2019 | Health and Medicine