Recent advances in DNA sequencing techniques in the fields of biology and medicine have led to a greater focus on the role of microbes on human health. Synthetic chemicals that are added to foods and hygiene products can affect the relationship between microbes and humans and human health.

Recent research conducted at UC Davis involving human and animal health and the issue of microbes is leading researchers to issue cautions about the excess use of synthetic chemicals, such as triclosan, in human hygiene products.

“One of the [perspectives] that we’re looking at most recently is how the environment and diet might affect the bacteria that live within us,” said Bruce German, a professor in the UC Davis Food Science and Technology Department, in reference to his work with UC Davis professor Bruce Hammock.

Hammock does research in the UC Davis Center for Environmental Health Science and has been conducting research with two UC Davis graduate students, Ray Zhang and Erika Fritsch.

“The chemical triclosan is found in numerous consumer products, like in antibacterial soap, face wash and toothpaste, and we are constantly exposed to this chemical through the products that we use,” Zhang said.

Researchers are concerned about the overuse of antibacterial soap and other hygiene products, since such overuse may lead to bacterial strains that are resistant to the synthetic chemicals used.  The existence of bacterial strains that exhibit resistance to common antibacterials can potentially lead to problems in public health and increased rates of infections.

“We are beginning to realize that the cloud of microbes that live in and on us and that live in and on plants and animals have profound effects on many aspects of our biology,” said Jonathan Eisen, a professor and researcher in the UC Davis Genome Center. Eisen recently gave a talk on TED.com titled “Meet your microbes.”

According to Eisen, widespread use of antibacterials is being viewed in a completely new light.

Leo Galland is the director of The Foundation for Integrated Medicine and author of the book “Power Healing: Use the New Integrated Medicine to Cure Yourself.” Galland agrees with Eisen’s assessment.

“Doing things randomly [can] destroy bacterial communities without a real clear idea of why you’re doing it [and] can definitely lead to unintended and adverse consequences,” Galland said. “It’s not necessarily a question of good bacteria and bad bacteria, because the functions of bacteria – the metabolic activities and the immune effects of bacteria on the human body – depend upon the specific milieu in which that interaction is taking place. So a particular organism might have beneficial effects in one milieu and negative effects in another.”

Galland stresses that “bacteria need to be treated with respect and we need to basically understand that our bodies are like planets.”

“We should continually be evaluating the benefits of [synthetic] chemicals and the [associated] risks,” stressed Hammock.

BRIAN RILEY can be reached at science@theaggie.org.

Shakira and Simple Plan had it right: Being in love is like being addicted. It’s strange to think that the pleasure we feel when eating is the same pleasure we get from winning a competition, taking a recreational drug or even being in love. In reality, the pleasure we get from these things all comes from the same place in the brain, and is a result of the same chemical reactions. Furthermore, the pain caused by losing these things also come from the same place as well. It is like a mirror tunnel in which our brains affect our relationships, which in turn affect our brains.

It is almost unnerving how similar these experiences are when looked at in terms of behavior and chemical reactions. Just look at any website or book that talks about the signs of addiction and you’ll see. Love and drug addiction both cause change in personality and attitude. Love and drug addiction both cause mood swings, irritability and outbursts. They both cause periods of hyperactivity, agitation and giddiness. And both can cause fear and anxiety.

If someone asked you to point to the part of your body where you physically feel love, you might point to the heart, cheeks, arms or legs. The range of answers you would get to this question would cover the entire body. However, to fully answer this question, you would want to point to the nucleus accumbens, a part of the limbic system, and the prefrontal cortex. When exposed to certain neurotransmitters, the nucleus accumbens creates an association between pleasure and a stimulus such as food, drugs or sex, and will facilitate a future desire for these stimuli.

The dopamine and serotonin released from eating, taking a drug or being in love all work the same way in the nucleus accumbens and will condition the brain to heavily desire those things. So when these stimuli are in abundance, the brain works to ensure that you keep coming back for more; more food, more drugs, or more love. But what happens when these stimuli disappear?

When two people are in a relationship, they share more than just emotions. They share responsibility, assets, germs and immune function, and social identity. This brings a whole new meaning to “getting under each other’s skin”: Once all the stimuli associated with an amorous relationship are gone, the body experiences a crushing emptiness. Point to the part of your body where you feel this. Is it the chest that weighs a thousand pounds, weak arms and legs, clouded mind? You would actually have to point to the same part of the brain that processes physical pain, rejection and being attacked: the dorsal anterior cingulate cortex (ACC). The ACC is a “collar” of brain tissue that wraps around the corpus callosum, the part of the brain that connects the left and right hemispheres. When these two regions interact, they play a major role in regulating blood pressure, heart rate, decision making, reward anticipation, empathy and emotion.

Many people may be familiar with another fascinating quirk of the brain: the amazing ability to forget every negative aspect of a relationship and only remember the positive, pleasure-bringing parts. It is this quirk that drives many people to stay in bad situations. This is the same process that makes drug addicts keep returning to the needle and powder despite being fully aware of the consequences. The decision-making ability of the ACC and the corpus callosum becomes horribly reduced when faced with the potential loss of pleasurable stimuli such as a drug or love. We are so addicted to the pleasurable stimuli that love can bring that we will subject ourselves to countless hardships.

So, love is just a chemical state of being. But flowers and chocolate never hurt anyone.

HUDSON LOFCHIE can be reached at science@theaggie.org.

Beauty may be only skin deep, but for scientists working at the scale of single molecules, it can go deeper still. A joint research team from UC Davis and Peking University has shown for the first time how the active ingredient in cosmetic treatments such as facial peels function at the molecular level to produce the exfoliation effect by which newer, fresher skin cells are exposed.

In a paper published in the Journal of Biological Chemistry, the authors report that glycolic acid, a common ingredient in topical anti-wrinkle creams, causes skin cells to die by activating a specific ion-channel protein – a complex molecule which regulates the passage of electrically charged molecules into and out of the cell membrane – allowing an influx of calcium.

“Calcium is a very important ion for life because calcium is a signal ion used in biology in many, many ways,” said Dr. Jie Zheng, professor of physiology and membrane biology at the UC Davis School of Medicine and a co-author of the study. “But if we let a lot of calcium into the cell, the intracellular signaling gets totally screwed up and the cell will die.”

Glycolic acid is part of a family of molecules known as alpha hydroxyl acids (AHAs). Until now it was thought that AHAs worked by loosening the bonds between already dead cells and the underlying live tissue, rather than killing the cells with the help of a protein sensitive to the acidification caused by AHA molecules diffusing into the cell’s interior.

This protein, called TRPV3, is part of a family of proteins that have been studied for their ability to act as heat and pain sensors, helping to maintain a constant body temperature and regulate our physiological reactions to “hot” foods such as chilis. In what Zheng described as “a total surprise,” TRPV3 was found to be highly expressed in the skin.

“The channel was first discovered in sensory neurons, and it was discovered as a heat sensor,” Zheng said. “Later on people realized that actually this channel is expressed in the skin a lot, and people started to wonder, ‘Why is it there?’”

The “why” is still an open question, since the role of TRPV3 under normal physiological conditions remains unclear. However, a major part of the “how” of TRPV3’s role in exfoliation has been established for the first time.

Zheng jokes that this process wasn’t evolved for the purpose of making us look prettier. Instead, he says, “we found by accident a way to use this process [in cosmetics] without realizing it.”

However, with a greater understanding of the mechanisms involved, it may be possible to mitigate side effects such as itching and inflammation.

“I think the [cosmetics] industry was doing this wrong,” said Zheng. “We use a very strong dose of acid, of course we get rid of the old skin on the surface. But what happens after that? What we need to do is find ways to promote that process without hurting the good cells underneath. So I think if the industry realized that, and finds ways to do that, we may have some much better products.”

Zheng says he doesn’t know to what extent anyone in the cosmetics industry is taking notice. For his part, the more interesting questions surround the function of TRPV3 in human health. For example, a genetic mutation in TRPV3 results in a skin disorder known as Olmsted syndrome, characterized by mutilated patches of skin and whose symptoms include severe itching.

“What is probably as important, if not more important, is to know whether we can use [this knowledge] to cure disease or treat conditions to improve human life. Those are things that are arguably more important. And of course to me as a scientist, it is just as interesting to simply understand how nature works.”

OYANG TENG can be reached at science@theaggie.org.