Navigation Links
Brainy genes, not brawn, key to success on mussel beach

It's hard being a mussel: you have to worry about hungry starfish and even hungrier humans, not to mention an environment that can change your body temperature 50 degrees Fahrenheit in just a few hours.

"It's one of the most variable habitats on Earth," said USC biologist Andrew Gracey. "Mussels can spend part of the day bathed in cool Pacific seawater and the other part baked under the California sun."

Gracey led the first real-time molecular sampling of mussels in their natural habitat, the results of which appear online Oct. 9 in the journal Current Biology.

The researchers found that the hardy mollusks alternate between expressing genes associated with eating and genes associated with growing.

Scientists have thought that mussels survive their harsh home on the rocks by just being tough, but this study suggests a more sophisticated strategy.

"They spend part of the day respiring, and doing metabolic processes, and then the other part of the day switching to cell division," Gracey explained.

Because their environment is so unpredictableat low tide mussels could scorch on a sunny day and get soaked on a stormy onethese regular cycles were unexpected.

"To be honest, I first thought they'd be wasting their time to be constantly switching on this gene and switching off that gene," Gracey said.

The scientists also found that as the environment became harsherlike higher up the rocksthe oscillations in gene expression became more pronounced.

Mussels use genes to weather the heat

In addition to cyclic expression, the study found that mussels use two sets of genes to respond to heat stresssometimes reacting to temperature changes in seconds.

"Day-in, day-out, they switch on a particular set of genes associated with routine heat stress, but when the day got very hot we saw this other battery of genes dealing with really extreme temperatures," Gracey said.

The first set of genes triggers the formation of chaperones that prevent proteins from unraveling, while the second set creates proteins that shepherd damaged material away.

This could have implications for climate change and how a key species like musselsfundamental to the ecology of inter-tidal rocky zoneswould adapt to a hotter world.

In addition, there are implications for understanding sudden summer mortality syndrome, a mysterious die-off that can devastate oyster farms, and which is believed to be linked to a stress event like heat.

Gene oscillation as survival strategy

Expressing genes in waves appears to be a survival strategy, one that has been seen in lab experiments involving yeast.

"There are certain physiological processes that are fairly incompatible, like respiration and cell division," Gracey explained.

Respiration creates free radicals, and if an organism undergoes cell division at the same time, those free radicals could damage DNA. (This is partly why antioxidants in green tea and pomegranates are popular these days, since they remove free radicals.)

By keeping respiration and cell division separate, mussels can decrease the chances of such cell damagean advantage in such extreme conditions.

What controls the cycles?

In humans, the circadian rhythm is also a cycle that involves waves of gene expression, but unlike the mussel cycles, it has consistent intervals regulated by light.

"Periods are typically constant, and typically they're following something related to a 24-hour cycle," Gracey noted. "Our data doesn't conform to that."

It's not yet clear what is driving the cycles in mussels. It could be temperature, how much time is spent out of the water, or the opportunity to feedbut it's hard to pin down a single variable.

(A new grant from the National Science Foundation will help Gracey and colleagues tackle that question through lab simulations.)

Study methods

The scientists collected genetic material every three to four hours over three days, sampling mussel beds just south of the Monterey Bay Aquarium in California. They also installed "robo-mussels"chips sealed in siliconto record body temperature.

Back in the lab, the DNA was sequenced and bound to 10,000 points on a "gene chip," or DNA microarray.

They then extracted RNAthe messenger that commands expression of a certain genefrom the samples at the 20 successive time points.

RNA from two consecutive points was then converted to DNA, which was labeled with two different dyes. These two types of DNA were then allowed to bind with different points on the microarray, which correspond to different points on the mussel genome.

Thanks to the dyes, the scientists could then observe which sample from which time point bound relatively more to a specific part of the mussel genome.

When this was determined, the functions of those genes that were expressed more at that point in time could be inferred based on their similarity to genes in public databases.


Contact: Terah DeJong
University of Southern California

Related biology news :

1. NIHs Genes, Environment and Health Initiative adds 6 studies
2. Location, location, location important for genes, too
3. Researchers report the cloning of a key group of human genes, the protein kinases
4. Genes, Environment and Health Initiative invests in genetic studies, environmental monitoring
5. Gene regulation, not just genes, is what sets humans apart
6. University success at national engineering awards
7. Army can boost mission success by better managing
8. HPV DNA test identifies cervical pre-cancerous disease in developing countries with 90% success rate
9. Gap junction protein vital to successful pregnancy, researchers find
10. Successful series of measurements in Arctic sea ice
11. Dont count on long-term success in climate policy, warns paper in Decision Analysis
Post Your Comments:
Related Image:
Brainy genes, not brawn, key to success on mussel beach
(Date:11/19/2015)... Nov. 19, 2015  Based on its in-depth analysis ... recognizes BIO-key with the 2015 Global Frost & Sullivan ... & Sullivan presents this award to the company that ... the needs of the market it serves. The award ... and expands on customer base demands, the overall impact ...
(Date:11/18/2015)... ALBANY, New York , November 18, 2015 /PRNewswire/ ... Transparency Market Research has published a new market report ... Share, Growth, Trends, and Forecast, 2015 - 2021. According to ... bn in 2014 and is anticipated to reach US$29.1 ... 2015 to 2021. North America ...
(Date:11/17/2015)... LIVERMORE, Calif. , Nov. 17, 2015  Vigilant ... has joined its Board of Directors. ... Vigilant,s Board after recently retiring from the partnership at ... owning 107 companies with over $140 Billion in revenue.  ... performance improvement across all the TPG companies, from 1997 ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... , Nov. 24, 2015  Twist Bioscience, ... that Emily Leproust, Ph.D., Twist Bioscience chief executive ... Healthcare Conference on December 1, 2015 at 3:10 ... in New York City. --> ... . Twist Bioscience is on Twitter. Sign ...
(Date:11/24/2015)... Telbec/ - ProMetic Life Sciences Inc. (TSX: PLI) (OTCQX: PFSCF) ... Laurin , President and Chief Executive Officer of ProMetic, will ... 27 th Annual Healthcare Conference to be held at ... st , at 8.50am (ET) and ProMetic,s management ... The presentation will be available live via a webcast accessible ...
(Date:11/24/2015)... , November 24, 2015 , ... a European healthcare fund ... companies will work closely together in identifying European breakthrough technologies ... need. The collaboration is underpinned by a significant investment by ... is the first investment by Bristol-Myers Squibb in a European ...
(Date:11/23/2015)... 23, 2015   Ceres, Inc . (Nasdaq: ... results for the fiscal year ended August 31, 2015 ... --> --> During fiscal year ... feed products with a better balance of yield, energy ... agreements with several leading crop input providers and made ...
Breaking Biology Technology: