BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: bacteria communication

A Baby Beetle’s Nursery is.. In a Dead Mouse?!

Two Parent Burying Beetles in a Dead Rodent! Gross!

Typically, death for animals is experienced at the end of one’s life, but this is reversed for a certain species of carrion beetle, Nicrophorus vespilloides or burying beetle, in which infant beetles are born and raised within dead mice carcasses. In this mice carcass, parent beetles frequently tend to the dead animal by soaking it with their own oral and anal secretions, providing the baby beetle with a much needed dark microbial film. This bacterial goo actually closely resembles the parent beetle’s gut microbiomes, allowing for the baby beetle to truly thrive as an offspring of this beetle.

But why give these baby beetles this goo within a dead carcass? What benefit would that ever give to an insect?

In every living thing, there is sphere of personal bacteria that provide much needed life benefits as well as qualities like your own stench. Plus, bacteria can even join together through various forms of cellular communication, making an almost impenetrable microfilm biome for bacteria to live in, as seen in plaque on human teeth. This same function is what helps support infant beetles with necessary nutrients and life benefits by keeping the cadaver fresh and capable of sustaining youngster life. Plus, it even causes dead bodies to smell actually not terrible, but instead more pleasant! Crazy! “What burying beetle parents can do with a small dead animal is remarkable,” says coauthor Shantanu Shukla of the Max Planck Institute for Chemical Ecology in Jena, Germany.  “It looks different. It smells different. It’s completely transformed by the beetles.”

If these insects aren’t exposed to these microbiomes as a child, there could be some serious detrimental effects. As shown by Shukla’s lab work, larvae grown in cadavers that were swept clean of biofilm by Shukla and her colleagues used their food less efficiently and gained less weight (“roughly third less weight per gram than those who had their parents goo”).

But, the parents are not the only ones who manipulate the carcass, which can be seen here. As parent beetles and tended to their goo in the body and guarding their children, the infant beetles also add their own secretions to the dead mouse and also eat away the bacteria as well as the entire mouse body. “What will remain is the tail of the mouse,” Shukla says, “and the skull and a few pieces of skin.”

Isn’t it simply crazy how much bacteria can contribute to the growth of a baby insect as well as its impact on even a dead animal? Comment below about what YOU think about this!

Genetic Engineering on Gut Bacteria!?

E. coli on MAC – Photo credit to VeeDunn on flickr under Creative Commons License

Researchers at the Wyss Institute at Harvard University has successfully tested a genetically engineered signaling bacteria within a mouse’s gut. Having known that the many types of bacteria in the human gut can communicate through “quorum sensing” , researchers set to observe a particular type of quorum sensing, acyl-homoserine lactone sensing, which has not been observed in the mammalian gut. They wanted to test if using that particular type of signaling could create a genetically engineered bacterial information transfer system.

Using a strain of E. coli bacteria, they created two different colonies, each with a different genetic change: one was the “signaler”, it contained a copy of the luxl gene which produces a quorum-sensing molecule when activated, and the other was the “responder”, which contained a “cro” gene turning on a “memory element” in the responder.  This “memory element” expressed another copy the the pro gene, which allowed for the loop to continue, and the LacZ gene, which made the bacteria turn blue!

LacZ gene expression – Photo credit to Viraltonic on Wikimedia Commons under Creative Commons License

The researchers analyzed fecal samples of mice given signaler and responder E.coli and they were happy to see the signal transmission, blue coloring, was evident in the samples. This result meant that they had created a functional communication bacteria system in the mouse’s gut.

The researchers then repeated their experiment with a different type of bacteria, S. Typhimurium, as the “signaler” and E. coli as the “responder”, and they were pleased to see similar successful results.  They were able to successfully confirm that is possible to genetically engineer these communication circuits between different species of bacteria in the mammalian gut microbiome.

These tests are merely stepping stones for the bigger goal of creating genetically modified bacteria that will help humans in various different ways: detecting and or curing diseases, improving digestion, and so on. Isn’t it cool that something we barely realize is inside us has such a developed communication system that we might soon be able to cultivate more benefits from? What do you think would be some other benefits to be being able to genetically modify our gut microbiomes?

 

 

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