Study of insect bacteria reveals genetic secrets of symbiosis

Study of insect bacteria reveals genetic secrets of symbiosis

The net result: The bacteria get a comfy mealybug home, and the bugs get the nutrition they need to live.

University of Montana microbiologist John McCutcheon describes such mutually beneficial relationships used to solve life's little problems as "almost hilariously complicated. But animal-bacterial relationships are extremely common in nature, and it's my goal in life to help people understand that it's normal."

McCutcheon and his research partners recently delved deeper into the genes involved in the "tripartite nested mealybug symbiosis," and their work was published in the June 20 issue of Cell, a scientific journal. The researchers discovered the already complex three-way symbiosis actually depends on genes from six different organisms -- three more than the number of species that currently exist in the symbiosis.

Tremblaya princeps is the larger of the two bacteria species living within special organs inside mealybugs. Tremblaya houses the smaller bacterial species, Moranella endobia, within its cytoplasm. But what makes Tremblaya truly odd is the size of its genome, or genetic code. With only 120 genes, its genome is the smallest known and smaller than many scientists consider necessary for life. By comparison, common E. coli bacteria have about 4,200 genes and humans have about 21,000.

"We wanted to discover how this genome got so small," McCutcheon said. "We suspected Tremblaya's genome may have gotten smaller by transferring genes to the host animal, which is called horizontal transfer."

The researchers looked for genes in the mealybug genome that resemble bacteria genes. However, after extensive analysis they only found one weak possibility for horizontal transfer from Tremblaya.

"Our hypothesis that Tremblaya was transferring genes to the host was dead wrong," said McCutcheon. They did, however, find 22 other bacterial genes mixed in with the mealybug code -- genes that seem to support activities missing in Tremblaya, Moranella and the mealybug.

How can this be?

"The genes are probably from historical bacterial infections," McCutcheon said. "These bacteria are no longer present in the mealybugs we work with, but their horizontally transferred genes are, and these genes allow the symbiosis to work."

The research team also examined a strain of Tremblaya that doesn't have Moranella living inside it. This variety employs about 50 more genes than the one containing Moranella, which strongly suggests Moranella plays a key role in allowing the insect-dwelling Tremblaya to operate with such a tiny genome.

McCutcheon said Tremblaya, with its shrinking genome, in many ways resembles organelles called mitochondria -- tiny structures found within all plant and animal cells that scientists believe started out as symbiotic bacteria in the early history of life. The mealybug/bacteria relationship he studies may illustrate one pathway bacteria take in becoming essential and highly integrated components of other cells.

"So this research really touches on some fundamental questions of the origin of life," he said. "It's exciting to see if we can get some insight into the origin of organelles."

McCutcheon said this study involved an international cast of 12 collaborators. Filip Husnik, the study's lead author, is a Czech doctoral student from the University of South Bohemia who worked in McCutcheon's UM lab. Other team members were from Japan, England, California, Utah and Florida.

The study was funded by a $529,000 grant from the National Science Foundation.

"Our work illustrates how an animal's interactions with bacteria can drive hidden organismal complexity," McCutcheon said. "A tree is more than a tree, and an animal is more than an animal. They are really mosaics of plants and animals and bacteria all working together."

Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

We have built up long term business relationship with about many companies which are stockers and authorized agents. we have a steady and reliable supply to meet customer's demands to the greatest extent .Confidently, we are able to lower your cost and support your business with our years of professional service.

SUV System Ltd is Electronic Components Distributor Supplies,Find Quality Electronic Components Supplies Products IC(Integrated Circuits),Connectors,Capacitor,Resistors,Diodes,Transistors,LED at Suvsystem.com. Sourcing Other Energy, Environment, Excess Inventory Products from Manufacturers and Suppliers at Suvsystem.com

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

SUV System Ltd insists on the managing faith ofsincereness,speciality,foresight, win-win,so we build up stable-relationship customers located all over the world, including the States, Europe, Argentina, UAE, Malaysia, Australia,and India etc

we are focus on the following fields,and hope we can help you.

C0402C0G1C1R1B C0402C0G1C150J C0402C0G1C130J C0402C0G1C130G C0402C0G1C120J C0402C0G1C120G C0402C0G1C110J C0402C0G1C110G C0402C0G1C100E C0402C0G1C100D C0402C0G1C0R5C C0402C0G1C090D C0402C0G1C090C C0402C0G1C090B C0402C0G1C080D C0402C0G1C080C C0402C0G1C080B C0402C0G1C070D C0402C0G1C070C C0402C0G1C070B C0402C0G1C060D C0402C0G1C060C C0402C0G1C060B C0402C0G1C050B C0402C0G1C040C C0402C0G1C040B C0402C0G1C030C C0402C0G1C020C C0402C0G1C020B C0402C0G1C010C C0402C0G1C010B C0402C100C5GAC C0402C100C3GAC C0402C0G1C9R1D C0402C0G1C9R1B C0402C0G1C8R2D C0402C0G1C8R2C C0402C0G1C8R2B C0402C0G1C7R5D C0402C0G1C7R5C
http://www.suvsystem.com/a/3081.aspx