The human skin cell

The purple in the center is the cell’s nucleus. Surrounding it are wispy blue and white microtubules and filaments that make up the cell’s cytoskeleton.

The cytoskeleton is made from protein structures called microtubules—the wispy threads surrounding the purple DNA-containing nucleus—and filaments of a protein called actin, seen here as the fine blue meshwork in the cell periphery. Both actin and microtubules are critical for growth and movement.

Unlike our own bony skeleton, which keeps the same arrangement throughout our lives, the cellular cytoskeleton is dynamic, continuously morphing in response to cellular signals. In this image, cytoskeleton remodeling of the skin cell was triggered by addition of a growth factor, which produced protrusions of the cell edge and the characteristic “fried egg” shape of this cell. These protrusions have little “feet” that help the cell move forward. The Wittmann lab recently used these skin cells to model the complex choreography by which microtubules control cell movement.

Learn more about the cytoskeleton and this image, taken by UCSF cell biologist Torsten Wittmann.

The gluten network in a bagel vs. a pie

Gluten develops in dough when two wheat proteins found in flour (glutenin and gliadin) are mixed with water. Because parts of these proteins don’t like to interact with water, the proteins begin to stick to each other much in the same way oil droplets come together when suspended in water. As a flour-water dough is mixed, the glutenin and gliadin molecules interact to form a protein network.

These networks give structure and stability to dough. Although dense networks are great for chewy bread dough, they are less than ideal for flaky, tender pie crust. An ideal pie dough has as just enough gluten to hold everything in the dough together. And while gluten development can be minimized by adding only scant amounts of water and handling the dough as little as possible, this is easier said than done.

What flour is the best flour for pie crust? This is a contentious question that has a variety of answers depending on personal preference, but the type of flour you use can have a major effect on the final texture of your crust. The protein content of flour, based on the type of wheat the flour was made from, will affect the extent of gluten formation in your dough. Bread flour has particularly high protein content, which can make pie crust dense and tough. Flours with lower protein content, such as pastry flour or cake flour, will create less extensive gluten networks and can produce a more tender crust.

Use science to make the best pie ever:

Sushi Meets Science: The Wasabi Receptor

Researchers at UCSF have pulled aside the curtain on a protein informally known as the “wasabi receptor,” revealing at near-atomic resolution structures that could be targeted with anti-inflammatory pain drugs.

The newly visualized protein resides in the cellular membrane of sensory nerve cells. It detects certain chemical agents originating outside our bodies — pungent irritants found in substances ranging from wasabi to tear gas — but is also triggered by pain-inducing signals originating within, especially those that arise in response to tissue damage and inflammation.

With many copies of the proteins suspended in this glassy ice, like insects trapped in amber, the researchers capture as many as 100,000 images, then computationally combine these thousands of two-dimensional views to generate the three-dimensional structure of the protein.

“The pain system is there to warn us when we need to avoid things that can cause injury, but also to enhance protective mechanisms,” said David Julius, Ph.D., professor and chair of UCSF’s Department of Physiology. “We’ve known that the protein is very important in sensing environmental irritants, inflammatory pain, and itch, and so knowing more about how it works is important for understanding basic pain mechanisms.”

Read more about The Wasabi Receptor

Sex, Aggression & Damselflies

Aggression between two different species of animals is surprisingly common. But what exactly are they fighting over?

Male aggression towards potential reproductive rivals could explain much of it.

UCLA biologists observed and analyzed the behavior of several species of damselflies. Male damselflies typically ignore males of another species when they fly into their territory — unless they’re attempting to mate with a female damselfly.

Female damselflies almost always refuse to mate with males of a different species, said UCLA’s Gregory Grether, but that doesn’t stop some males from trying, especially in cases where the females of both species have similar wing color.

“Male damselflies often have difficulty distinguishing between females of their own species and another species when making split-second decisions about whether to pursue a female,” Grether explained.

Damselflies typically live only a couple of weeks, and have few mating opportunities.

The biologists documented some cases where aggression between species has essentially disappeared because of substantial divergence in wing coloration.

Read more about the damselfly aggression and what it can tell us about human evolution

The world’s first sustainable surfboard made of algae

UC San Diego biology and chemistry students have created the world’s first algae-based, sustainable surfboard.

The project began several months ago when undergraduate biology students began working with a group of undergraduate chemistry students to solve a basic chemistry problem: how to make the precursor of the polyurethane foam core of a surfboard from algae oil.

Polyurethane surfboards today are made exclusively from petroleum.

“Most people don’t realize that petroleum is algae oil,” explained Mayfield. “It’s just fossilized, 300 million to 400 million years old and buried deep in underground.”

The chemistry students figured out how to chemically change the oil obtained from laboratory algae into different kinds of “polyols.” Mixed with a catalyst and silicates in the right proportions, these polyols expand into a foam-like substance that hardens into the polyurethane that forms a surfboard’s core.

Although the board’s core is made from algae, it is pure white and indistinguishable from most plain petroleum-based surfboards. That’s because the oil from algae, like soybean or safflower oils, is clear.

“This shows that we can still enjoy the ocean, but do so in an environmentally sustainable way,” added Stephen Mayfield, a professor of biology and algae geneticist who headed the effort.

Read how UC San Diego is surfing into a greener future

 

 

How One Scientist Is Helping Plants Survive California’s Worst Drought

Every living thing has its own natural responses to stress.

When critical nutrients are in short supply, our bodies, for example, find ways to maintain normal function until those nutrients are replenished. Plants do the same. In drought conditions, natural processes kick in to keep them alive until they can be watered again.

When faced with a water shortage, plants produce a stress hormone known as abscisic acid (ABA), which signals the plant to consume less water. ABA binds to a specific protein receptor in the plant, signaling stomata—or unique guard cells—to close and reduce the amount of water lost. This receptor is so important that its discovery by UC Riverside’s Sean Cutler, his team and others was listed as one of 2009′s breakthroughs of the year by Science magazine.

To help plants survive extreme drought conditions, some have tried spraying ABA directly on crops during water shortages. The move can improve crop yields, but ABA is expensive to produce and breaks down easily, even before a plant can absorb and use it.

Read more about how Sean Cutler is helping plants survive California’s worst drought

Image credit: Adam Shomsky

How Do Our Bodies Fight Off Dangerous Chemicals?

We’re all subjects in a massive experiment. Humans have created about 80,000 synthetic industrial compounds — including plastics, the flame retardants that cover our sofas, and pesticides. These compounds have structures that are not commonly seen in nature and present a risk to our health. Everybody on the planet is exposed.

It’s important to understand what these substances are doing to our bodies so that scientists can create a rule book for making these chemicals safer.

The challenge to understanding how dangerous compounds get into our body is complex. The way we have been doing this in the past is to test if a synthetic compound dissolves in fat. If it does then theres a high likelihood that it can easily enter our body’s cells where it can cause harm.

The problem with this method is that it doesn’t always accurately predict how much a compound accumulates in organisms. A historic example of this is DDT which was used on crops to get rid of pests, but ultimately found its way through the food chain. It’s now considered a risk factor for breast cancer in humans.

At UC San Diego’s Scripps Institution of Oceanography, Amro Hamdoun is looking at the biological properties of how these compounds interact with cells. The focus is on how the cell decides which compounds to let in and which ones to eliminate.