Navigation Links
A Dicty mystery solved
Date:5/27/2010

The title sounds like a crime novel on a dime-store shelf. But "An Invitation to Die" is quite literal in its meaning. And the prime suspect is very, very small.

Rice University evolutionary biologists reported in a paper published this week that the first cells to starve in a slime mold seem to have an advantage that not only helps them survive to reproduce, but also pushes those that keep on eating into sacrificing themselves for the common good.

The paper by Rice graduate student Jennie Kuzdzal-Fick and her mentors, David Queller and Joan Strassmann, Rice's Harry C. and Olga K. Wiess Professors of Ecology and Evolutionary Biology, appears in the online edition of the Royal Society journal Biology Letters. The paper's full title is "An Invitation to Die: Initiators of Sociality in a Social Amoeba Become Selfish Spores."

It helps to understand what Dictyostelium discoideum are, and how they behave. The single-cell organisms collectively known as slime mold live independently and feed on bacteria until the food runs out. When that happens, adjacent cells aggregate into a single slug and move as a slime-coated unit toward heat and light, which indicate the presence of a good place to form a fruiting body. At their destination, amoebas at the front sacrifice themselves, dying to form a cellulose stalk. Others in the colony climb aboard and become spores that sit on top, where small organisms disperse them to nutrient-rich places.

Common wisdom dictates that the first cells to starve would be the first to die. "Because they initiate aggregation into the social stage, we were interested in finding out what their reproductive fate was," Kuzdzal-Fick said. "For a lot of reasons, it would make more sense if the first cells to starve altruistically formed the stalk."

But that's not how it happens, and it took her months of detective work to track down the clues. Kuzdzal-Fick employed a complex sequence of raising, selectively starving and recombining clones of D. discoideum so that pre-starved cells could be tracked.

When the organisms were allowed to form fruiting bodies of stalks and spores, fluorescent tags revealed that pre-starved cells made up a much higher percentage of the spores than expected.

"They ought to be weaker than the other cells," Queller said. "They're starving first. But when they're under development, they turn on whole sets of genes that do all the things they need to do in development, and among those genes are probably ones for offense and defense. They're deploying the tools to obtain their preferred outcome -- which is to be in the spores -- before the other guys are doing it."

"You could view them like an army, where one side is still polishing its weapons, but the other side has seen them and is putting bullets in their guns," Strassmann said. "Even though they may be hungry and have worse weapons, they see the enemy and they're turning on those weapons."

Strassmann said Kuzdzal-Fick has a way with single-cell beings. "This experiment turned out to be technically very difficult, and anyone else would have had a hard time completing this study. She's just a wizard at getting these things to behave," Strassmann said of her graduate student, who also worked in the Strassmann-Queller lab as an undergraduate at Rice. Kuzdzal-Fick expects to defend her thesis in the fall.

"Our best students really pay attention to their cells," Strassmann said. "They listen to their organisms. They know if their cells are happy, they know if they're not.

"If you have a sick lion or zebra, or even a sick mouse or wasp or fly, they look droopy and you can see it. You have to develop that exact same sense for a single-celled organism you can see only through the microscope."


'/>"/>

Contact: David Ruth
druth@rice.edu
713-348-6327
Rice University
Source:Eurekalert

Related biology news :

1. Dictyostelium cells shown to lay breadcrumb trail as first step in multicellular formation
2. Scripps Research scientists solve mystery of fragile stem cells
3. Experts gather to solve mystery of largest recorded die-off of great whales
4. U-M researchers solve a molecular mystery in muscle
5. Scientists unlock mystery in important photosynthesis step
6. Brown biologist solves mystery of tropical grasses origin
7. Green plant transport mystery solved
8. Coal from mass extinction era linked to lung cancer mystery
9. How people work ... and the fingerprint mystery
10. Mystery solved: Facial cancer decimating Tasmanian devils likely began in Schwann cells
11. Mystery of golden ratio explained
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/19/2016)... April 20, 2016 The new ... a compact web-based "all-in-one" system solution for all door ... reader or the door interface with integration authorization management ... control systems. The minimal dimensions of the access control ... the building installations offer considerable freedom of design with ...
(Date:4/15/2016)... 15, 2016 Research and ... Biometrics Market 2016-2020,"  report to their offering.  , ... , ,The global gait biometrics market is expected ... the period 2016-2020. Gait analysis generates ... be used to compute factors that are not ...
(Date:4/13/2016)... 13, 2016  IMPOWER physicians supporting Medicaid patients in ... new clinical standard in telehealth thanks to a new ... higi platform, IMPOWER patients can routinely track key health ... mass index, and, when they opt in, share them ... to a local retail location at no cost. By ...
Breaking Biology News(10 mins):
(Date:5/26/2016)... Despite the volatility that continues to envelop the ... research on ActiveWallSt.com directs the investor community,s focus on the ... ), Cerus Corp. (NASDAQ: CERS ), Arrowhead Pharmaceuticals ... Inc. (NASDAQ: FPRX ). Register with us today ... On Wednesday, shares in Massachusetts ...
(Date:5/26/2016)... ... May 26, 2016 , ... FireflySci ... used in leading laboratories all over the globe. Their cute firefly logo has ... manufacturing awesome cuvettes, FireflySci makes spectrophotometer calibration standards that never require recalibration. ...
(Date:5/25/2016)... ... May 25, 2016 , ... The Ankle Plating System 3 ... to address fractures of the distal tibia and fibula. This system marks Acumed's ... System 3 is composed of seven plate families that span the lateral, medial, ...
(Date:5/25/2016)... ... , ... Scientists at the University of Athens say they have evidence that ... the research that could lead to one good one. Surviving Mesothelioma has just posted ... , The team evaluated 98 mesothelioma patients who got a second kind ...
Breaking Biology Technology: