Smoking cigarettes is not only the principle cause of chronic obstructive pulmonary disease (COPD), but it may change the body’s immune responses to bacteria that commonly cause exacerbations of the disease, according to new research in a mouse model.

“It is well established that smoking is the main risk factor for COPD. But our research also suggests that cigarette smoke substantially changes the immune response to bacteria, which means that patients with COPD who smoke are weakening their body’s ability to deal effectively with bacterial invaders. This may cause even further progression of the disease,” said Martin Stämpfli, Ph.D., an associate professor at McMaster University, the principle investigator of the study.

“We wanted to see whether and how cigarette smoke would change the inflammatory response to the bacteria that is the culprit behind many COPD exacerbations, nontypeable Haemophilus influenzae or NTHI.”

Their results were published in the second issue of April of the American Journal of Respiratory and Critical Care Medicine.

Dr. Stämpfli and colleagues tested the effects of cigarette smoke exposure on inflammation and immune response in mice that were exposed to cigarette smoke twice daily five days a week for either eight weeks or four days then challenged with an intranasal inoculation of NTHI. The cigarette smoke exposure roughly approximated that of an “average” human smoker (within the limitations of a model with differing metabolic processes.) Control mice were not exposed to cigarette smoke, but were inoculated with NTHI as were the cigarette smoke-exposed mice.

The researchers found that mice that were exposed to cigarette smoke, whether for four days or for eight weeks, showed distinct shifts in their immune-response profile, namely an increase in inflammation of the lungs after the NTHI challenge, increased weight-loss in response to the bacterial infection and, notably, a shift in the expression of inflammatory markers.

“Many interventions are developed with a homeostatic model in mind,” said Dr. Stämpfli. “However, if our findings are borne out in clinical research, they would indicate that treatment targets for smokers with COPD may be markedly different than in non-smokers. Smoking may change the underlying inflammatory pathways elicited after bacterial infection.”

Because of the shift in the inflammatory profile, the researchers wondered if it would have an effect on the efficacy of treatment with the usual corticosteroids.

Interestingly, they found that while the corticosteroid dexamethasone was effective in controlling the inflammation following bacterial challenge in both control and cigarette smoke-exposed mice, but it appeared to compromise the body’s ability to clear the bacteria from the lungs.

“This was true for both control- and cigarette smoke-exposed mice and raises questions about the long-term use of corticosteroids in COPD. Certainly, there is evidence that corticosteroid treatment reduces the number of exacerbations in patients with COPD. This, however, is associated with occurrence of pneumonia, which is mirrored by our results. Therefore, inflammation is not altogether bad in the context of a bacterial infection, as it is required to clear the bacteria. It is the excessive inflammation observed in smokers that is of concern, as it may lead to lung damage.”

The researchers note that the NTHI bacterium is an obligate human pathogen, and therefore an imperfect fit for a mouse model of COPD. “In the context of this present study, NTHI challenge was used as a tool to address the hypothesis of cigarette smoke exposure on the ensuing inflammatory response, and may not be perfectly suited to address pulmonary clearance, as a mouse-adapted pathogen may demonstrate different kinetics of clearance,” Dr. Stämpfli noted.

Dr. Stämpfli intends to focus future research on detailing the precise immunological changes elicited by cigarette smoke exposure. “We must have a better understanding of which inflammatory markers are changing and how in order to develop a better understanding of potential targets for interventions,” he said.

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LEXINGTON, Ky. (April 6, 2009) – The side effects of an experimental “gene-silencing” treatment that is currently being investigated for a variety of diseases are even more wide-ranging than previously discovered, according to a study by a University of Kentucky researcher.

Following up on groundbreaking research published last year in the journal Nature, Dr. Jayakrishna Ambati, a UK ophthalmologist , and his colleagues found that the new drug modality, siRNA (21-nucleotide small-interfering RNA), is toxic not only to blood endothelial cells, which line blood vessels, but also to the cells lining the lymphatic channels.

These findings reinforce the note of caution sounded by Ambati’s previous Nature study, which has been cited nearly 50 times and highlighted in special reviews in premier journals such as Cell and in Nature, which termed it “stunning.” But these side effects could themselves find useful application, for example, in cornea transplantation, where growth of new blood and lymph vessels is believed to be a major cause of graft failure.

The new findings are published in this week’s online issue of Proceedings of the National Academy of Sciences, the official journal of the U.S. National Academy of Sciences.

In the earlier study, the Ambati laboratory discovered previously unrecognized immune side effects of siRNA, which is currently in FDA trials for numerous diseases including age-related macular degeneration and life-threatening viral infections.

Specifically, they showed that in two different established animal models of new blood vessel growth, siRNA killed these cells by activating an immune receptor called toll-like receptor 3 (TLR3). This was a critical finding, as immune and blood vessel toxicities were not believed to occur with this pharmacologic technique. As a result, siRNA is now recognized as a new class of anti-vascular drugs that could potentially be used to treat some of the 10 percent of the world’s population suffering from neovascular diseases. However, this first study did not address other forms of specialized endothelial cells that exist in the human body, including those that line the lymphatic system, a critical component of immune responses. The new study found that siRNAs block not only blood vessels but also lymphatic vessels. In the cornea, the clear part of the eye, injury often leads to the formation of both blood and lymphatic vessels. In fact, the formation of lymphatic vessels after corneal transplantation is purported to be a major mechanism through which transplant rejection occurs. Ambati’s lab found that corneal injections of siRNA suppressed both blood and lymphatic vessel growth via endothelial cell toxicity.

Won Gil Cho, post-doctoral fellow, Dr. Romulo Albuquerque, and Dr. Mark Kleinman, researchers in the Ambati laboratory, also showed that siRNA directly activates TLR3, the first time this has been demonstrated in the literature. Addditionally, they showed, using time-lapse studies, that siRNA does not enter cells without a cell-permeating moiety such as cholesterol. This is important, because siRNA must enter cells in order to function as intended by specifically degrading intracellular messenger RNA bound for protein-forming machinery. Furthermore, this finding strengthens their finding that TLR3 positioned on the cell surface is responsible for mediating the toxic side-effects of siRNA. In concert with Sandro De Falco and Arturo Brunetti, researchers in Naples, Italy, they also found that siRNAs generically block blood and lymphatic vessel growth in muscle tissue as well. These findings illustrate this side effect of siRNA can occur in many parts of the body.

Ambati’s lab also reported last year in the New England Journal of Medicine that siRNA is deleterious to other cell types, such as the retinal pigmented epithelium, which is involved in age-related macular degeneration.

“This may be a broadly imprinted response in the mammalian immune system that is activated by siRNA,” Ambati said. “In terms of benefit, siRNA may be utilized in the treatment of diseases of the lymphatic system, including lymphangiomas for which there is currently no effective targeted pharmacologic intervention.”

Ambati is a Doris Duke Charitable Foundation Distinguished Clinical Scientist and a Burroughs Wellcome Fund Clinical Scientist in Translational Research. His laboratory is also supported by the National Eye Institute of the NIH, Research to Prevent Blindness, and American Health Assistance Foundation.

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Young adults with a genetic variant that raises their risk of developing Alzheimer’s Disease show changes in their brain activity decades before any symptoms might arise, according to a new brain imaging study by scientists from the University of Oxford and Imperial College London. The results may support the idea that the brain’s memory function may gradually wear itself out in those who go on to develop Alzheimer’s.

The research, published today in the journal Proceedings of the National Academy of Sciences, provides clues as to why certain people develop Alzheimer’s Disease (AD) and it may be a step towards a diagnostic test that identifies individuals at risk. The degenerative condition is the most common cause of dementia and it affects around 417,000 people in the UK.

The APOE4 genetic variant is found in about a quarter of the population. Not everyone who carries the variant will go on to develop AD, but people who inherit one copy of APOE4 have up to four times the normal risk of developing the late-onset variety of the disease. People who have two copies have around ten times the normal risk.

The researchers behind today’s study stress that most carriers of APOE4 will not go on to develop Alzheimer’s and carriers should not be alarmed by the study’s findings.

Differences in the region of the brain involved in memory, known as the hippocampus, have previously been shown in middle-aged and elderly healthy carriers of APOE4. However, the new Oxford University and Imperial study is the first to show hyperactivity in the hippocampus of healthy young carriers. It is also the first to show that APOE4 carriers’ brains behave differently even at ‘rest’.

The study used functional Magnetic Resonance Imaging (fMRI) carried out at the University of Oxford to compare activity inside the brains of 36 volunteers, with 18 carrying at least one copy of the APOE4 gene and 18 non-carriers acting as controls.

All the volunteers in the study were aged between 20 and 35 and all performed normally on tasks designed to test their cognitive skills.

The researchers looked at how the volunteers’ brains behaved while they were resting and also while they were performing a memory-related task. Even when the APOE4 carriers were resting, the researchers could see that carriers and non-carriers each had distinct patterns of brain activity. The fMRI scans showed visible differences in how the hippocampus was relating to the rest of the brain.

The researchers will now carry out a similar study of patients with mild cognitive impairment to explore how these differences in patterns of brain activity in young people may be associated with later changes.

Dr Clare Mackay, the lead author of the study from the Department of Psychiatry and the Centre for Functional Magnetic Resonance Imaging of the Brain at the University of Oxford, said: “We have shown that brain activity is different in people with this version of the gene decades before any memory problems might develop. We’ve also shown that this form of fMRI, where people just lie in the scanner doing nothing, is sensitive enough to pick up these changes. These are exciting first steps towards a tantalising prospect: a simple test that will be able to distinguish who will go on to develop Alzheimer’s.”

Dr Christian Beckmann, another author of today’s study from the Division of Neurosciences and Mental Health at Imperial College London, added: “Our brains are always active – our minds wander even when we’re not carrying out specific tasks. We were surprised to see that even when the volunteers carrying APOE4 weren’t being asked to do anything, you could see the memory part of the brain working harder than it was in the other volunteers. Not all APOE4 carriers go on to develop Alzheimer’s, but it would make sense if in some people, the memory part of the brain effectively becomes exhausted from overwork and this contributes to the disease. This theory is supported by studies that have found the opposite pattern in people who have developed Alzheimer’s, with these people showing less activity than normal in the memory part of the brain.”

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WINSTON-SALEM, N.C. – Carrying extra weight earlier in life increases the risk of developing problems with mobility in old age, even if the weight is eventually lost, according to new research out of the Sticht Center on Aging at Wake Forest University School of Medicine.

The study, funded by the National Institute on Aging and the Wake Forest University Claude D. Pepper Older Americans Independence Center, appears in the April 15 issue of the American Journal of Epidemiology.

“In both men and women, being overweight or obese put them at greater risk of developing mobility limitations in old age, and the longer they had been overweight or obese, the greater the risk,” said lead investigator Denise Houston, Ph.D., R.D., an assistant professor of gerontology at the School of Medicine and an expert on aging and nutrition. “We also found that, if you were of normal weight in old age but had previously been overweight or obese, you were at greater risk for mobility limitations.”

Houston added that dropping weight later in life can lead to problems with mobility because weight loss later in life is usually involuntary and the result of an underlying chronic condition.

The study is based on data collected in the Health, Aging and Body Composition study, which enrolled Medicare recipients in Pittsburgh, Pa., and Memphis, Tenn., between April 1997 and June 1998. Participants had to be well-functioning, living in the community, and free of life-threatening illness.

The researchers defined mobility limitation as difficulty walking a quarter-mile or climbing 10 steps. They analyzed information from 2,845 participants who were on average 74 years old. Participants reported no problems with mobility at the beginning of the study. Information on new mobility limitations was collected every six months over seven years of follow-up.

Using participants’ body mass index (BMI), a measurement equal to a person’s weight in kilograms divided by height in meters squared, at different age intervals, the researchers found that women who were overweight or obese (BMI of 25 or greater) from their mid-20s to their 70s were nearly three times more likely to develop mobility limitations than women who were normal weight throughout. The risk for men was slightly less – they were about 1.6 times more likely to develop mobility limitations, according to the study.

The study also found that women who were obese (BMI of 30 or greater) at age 50, but not in their 70s, were 2.7 times more likely to develop mobility limitations compared to women who were not obese throughout. Men who were obese at 50, but not in their 70s, were 1.8 times more likely to develop mobility limitations than men who never carried the extra weight.

Carrying extra weight can strain joints, hinder exercise and lead to chronic conditions, such as diabetes, arthritis and heart disease, that are directly related to the development of mobility limitations, Houston said.

The results are significant, Houston added, because the elderly population in the United States is growing, and is expected to double by the year 2030 to about 20 percent.

“Over the past couple of decades there has been a trend towards declining rates of physical disability in older adults,” Houston said. “However, the dramatic increase in overweight and obesity in the United States may reverse these declines and may lead to an increase in physical disability among future generations of older adults. The data suggest that interventions to prevent overweight and obesity in young and middle-aged adults may be useful in preventing or delaying the onset of mobility limitations later in life.”

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PHILADELPHIA (April 7, 2009) – It may be wise to trust the female nose when it comes to body odor. According to new research from the Monell Center, it is more difficult to mask underarm odor when women are doing the smelling.

“It is quite difficult to block a woman’s awareness of body odor. In contrast, it seems rather easy to do so in men,” said study lead author Charles J. Wysocki, PhD, a behavioral neuroscientist at Monell.

The researchers speculate that females are more attuned to biologically relevant information in sweat that may guide women when choosing a mate.

In the study, women and men rated the strength of underarm odors, both alone and in conjunction with various fragrances.

The fragrances were selected to test their ability to block underarm odor through a method known as cross-adaptation. Olfactory adaptation refers to the loss of sensitivity to an odor when one is constantly exposed to that odor. Olfactory cross-adaptation occurs when the nose adapts to one odor and then also becomes less sensitive to a second odor.

Sniffed alone, the underarm odors smelled equally strong to men and women. When fragrance was introduced, only two of 32 scents successfully blocked underarm odor when women were doing the smelling; in contrast, 19 fragrances significantly reduced the strength of underarm odor for men.

Wysocki noted that in earlier studies, men and women did not differ in their ability to cross-adapt to odors not from the body.

“Taken together, our studies indicate that human sweat conveys information that is of particular importance to females. This may explain why it is so difficult to block women’s perception of sweat odors,” he said.

Not only were women better smellers the men, but male odors were harder to block than female odors. Even though underarm odors from the two sexes didn’t differ in how strong they smelled, only 19 percent of the fragrances successfully reduced the strength of male underarm odor; in contrast, over 50 percent decreased intensity of female underarm odor.

In the study, one sensory panel evaluated fragrances for their ability to counteract female underarm odor; a second panel judged the effectiveness of fragrances against male odor. Each panel contained both men and women.

To make their odor evaluations, panelists sniffed vials of underarm sweat previously collected in the laboratory from volunteers.

Panelists first rated the intensity of underarm odor to provide a measure of the odor’s strength. They then continued to rate underarm odor intensity while sniffing a fragrance for 2-1/2 minutes.

A drop in intensity ratings for the underarm odor indicated that the fragrance was a successful cross-adapting agent, capable of neutralizing the odor.

“Men and women differ in how they perceive body odors from both their own and the opposite sex,” summarized Monell scientist George Preti, PhD, an analytical organic chemist who co-led the research with Wysocki. “Women are more aware of underarm odor and they appear to be detecting differences in odor quality.”

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HOUSTON – Brief stress management sessions prior to and immediately after surgery may have both short- and long-term benefit for men undergoing a radical prostatectomy for early-stage prostate cancer, according to research from The University of Texas M. D. Anderson Cancer Center.

The study, in the current issue of the Journal of Clinical Oncology, is the first to examine the benefits of psychosocial intervention for prostate cancer patients prior to surgery. It found that men who participated in the sessions experienced less short-term mood disturbance and better long-term quality of life, compared to patients who had the procedure but did not have any behavioral intervention.

Most psychosocial interventions in cancer of any type have been studied after patients have completed surgery, explained Lorenzo Cohen, Ph.D., the study’s senior author and professor in M. D. Anderson’s Departments of Behavioral Science and General Oncology, and director of the Integrative Medicine Program.

“We know that for men with early-stage prostate cancer, the time when they are making treatment decisions is very stressful,” said Cohen. “A radical prostatectomy is not without possible, very personal, consequences, including urinary incontinence and erectile dysfunction. Patients may also be worried about the uncertainty that the surgery will cure their cancer.

“From other areas of research, we know that going into a surgical setting overly stressed may increase a patient’s recovery time. With this study, we wanted to intervene in the pre- and post-surgical setting and try to help relieve stress and minimize mood disturbance, such as depression, anxiety and distress, both in the short- and long-term.”

For the randomized study, 159 early stage prostate cancer, radical prostatectomy patients were assigned to receive either: two 60-90 minute sessions of pre-surgical stress management intervention and brief booster sessions the morning of, and 48 hours following surgery; two 60-90 minute individual supportive attention sessions and boosters similar to the stress management group; or standard care. Assessments occurred before the sessions, one month before, one week before, and the morning of surgery, as well as six weeks, six and 12 months following surgery.

The stress management was based on aspects of cognitive behavioral therapy. Men in the stress management group met with a clinical psychologist and were taught simple behavioral techniques, including diaphragmatic breathing and relaxing guided imagery and cognitive therapy. Those in the supportive attention groups met with the same psychologist, but sessions were more general, and centered around open discussions. Patients in the standard care group did not receive any behavioral therapy.

For the stress management group, the men were exposed to an imagery experience of the day of surgery – all the sounds and sensations from pre-op, to the recovery room, to coming out of anesthesia – while they were in a relaxed state. They were then taught cognitive skills to work with negative thinking and realistic expectations – so that patients could better manage any unexpected side effects during their recovery or difficulty healing.

The researchers found that in terms of short-term effects, assessed at one week before and the morning of surgery, men in the stress management group had the lowest levels of mood disturbance followed by those in the supportive attention group, with patients in the no therapy group having the highest level, with the difference between the stress management and standard care groups being statistically significant.

During the long-term follow-up, assessed at six weeks, six and 12 months, patients in the stress management group reported a higher level of physical functioning and aspects of quality of life than patients in the other two cohorts; the difference between the stress management and standard care groups was statistically significant.

The largest difference between the groups was at the 12-month follow-up, when the standard care group reported lower levels for physical functioning than those who received the stress management intervention. It’s also interesting to note that at no point was there any statistical difference between the supportive attention and the other two groups, said Cohen.

Cohen and his team were surprised to see this level of difference in physical functioning during the long-term follow-up because the interventions in the pre- and peri-operative settings were so brief and mainly focused on aspects of stress management.

“We’re trying to understand what is potentially associated with a patient’s long-term quality of life and what was it that happened in the stress management group that resulted in a much better quality of life in the year post-surgery,” Cohen said.

“Before we can suggest that stress management is useful prior to surgery for all men undergoing a radical prostatectomy, we need to better understand the mechanism behind our findings, as well as understand for whom this type of intervention will be the most useful,” Cohen said. “However, that said, all diagnosed with cancer treatment should be encouraged to participate in any stress management program – be it mind-body, or cognitive in nature. We know that they are safe and may improve patients’ well-being and help them adjust to a cancer diagnosis.”

As a follow up, Cohen and his team are currently analyzing immune function and stress hormone levels from collected blood samples.

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10 TRUE LEMON GIFT PACKAGES

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5 TRUVIA GIFT PACKAGES

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1 $100 GIFT CERTIFICATE TO CARBSMART.COM

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MANY MORE PRIZES TO COME! Be looking for more posts of what you can win throughout the week. Thank you for reading and supporting the “Livin’ La Vida Low-Carb” blog.

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Results from a new study identify a biomarker that may be useful for predicting the outcome of treatment for neuroblastoma, the most common cancer in young children. The research, published by Cell Press in the April 7th issue of the journal Cancer Cell, also provides new information about the molecular signals that are involved in the progression of this often devastating pediatric cancer.

Retinoic acid (RA) is a metabolite of Vitamin A that has important influences over the processes of growth and differentiation. RA mediates gene expression by interacting with retinoic acid receptors (RARs) that, in the presence of RA, switch from repressing target genes to activating them. Because many targets of RA induce differentiation or cell death, RA is used as a therapeutic agent in many cancers, including neuroblastoma.

“Many neuroblastoma patients exhibit aggressive tumors with poor clinical outcome,” explains senior study author Dr. Rene Bernards from The Netherlands Cancer Institute. “While some of these aggressive tumors exhibit increased expression of the MYCN oncogene, little is known about the other genetic factors that control neuroblastoma progression.” Dr. Bernards and colleagues performed a genome-wide RNA interference screen to search for additional components of the RA signaling pathway that might be linked to neuroblastoma.

The researchers identified ZNF423 as a critical cofactor of RA-induced differentiation. Reduced expression of ZNF423 was led to a growth advantage and resistance to RA differentiation in neuroblastoma cells while increased expression of ZNF423 led to growth inhibition and enhanced differentiation. The researchers went on to show that ZNF423 interacts with the RAR?/RXR? nuclear receptor that is necessary for activation in response to retinoids.

Importantly, low expression levels of ZNF423 were associated with poor disease outcome in neuroblastoma patients, suggesting that the gene might be useful as a prognostic biomarker. “Expression levels of ZNF423 could significantly affect responses to both endogenous and pharmacological concentrations of RA in cancer patients, which may in turn influence the outcome of neuroblastoma,” offers Dr. Bernards. “Therefore, ZNF423 may be a useful biomarker for predicting responses to RA-based therapies, which are increasingly being used to treat neuroblastoma.”

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CAMBRIDGE, Mass., April 6, 2009 – AVEO Pharmaceuticals, Inc., a biopharmaceutical company leveraging breakthrough discoveries in cancer biology to discover, develop and commercialize targeted oncology therapies, today announced findings from its novel human-in-mouse (HIM) cancer model system, in which AVEO successfully created invasive human tumors from primary human breast tissue that develop over time in mice and mimic human tumor behaviors and response. The findings were published this week in the Early Edition of the Proceedings of the National Academy of Sciences.

More than 95 percent of oncology drugs entering the clinic fail, due in large part to the lack of predictive animal models in the preclinical development phases. AVEO scientists have developed a sophisticated cancer biology platform that provides models of human cancer more relevant than traditional mouse models known as xenografts. In the AVEO HIM model, normal human breast tissue is engineered to express oncogenes and is then introduced into mice where it forms human breast tissue in the mouse mammary microenvironment. The tumors which then develop spontaneously acquire common and distinct mutations during tumor progression. This process results in human tumors in mice that reflect their human counterparts in that they differ slightly from one instance to another, exhibiting natural genetic variation akin to that seen in patients.

“Historically, the xenograft models created to analyze how human cancers behave have not been accurate predictors of human responses to various therapeutic agents,” said Robert A. Weinberg, Ph.D., member, Whitehead Institute and professor of biology, MIT. “In contrast, tumor development in the HIM model proceeds through defined histological stages of hyperplasia, from ductal carcinoma in situ (DCIS) to invasive carcinoma. Moreover, HIM tumors display characteristic responses to a targeted therapy known to be effective in humans, specifically Herceptin. This represents a big step forward in developing xenograft models that will accurately predict patient responses to agents that are in preclinical development. The HIM model is an exciting, experimentally tractable human in vivo system that holds great potential for advancing our basic understanding of cancer biology and for the discovery and testing of targeted therapies.”

By employing a tissue recombinant system and a gene transduction system, researchers assessed the in vivo biological consequences of specific genetic alterations in the reconstituted breast tissue. Introduction of different combinations of oncogenes, such as HER2, KRAS, PI3 kinase and p53, into the tissue enabled the researchers to dissect the contribution of each gene to human tumor formation in the model.

The authors also demonstrated the utility of the HIM models for drug efficacy testing by treating the HER2 driven breast tumors with different HER2 antagonists. The resulting potent inhibition of HIM tumor growth correlates with what has been observed in the clinic.

“With the increasing knowledge of specific genetic alterations in breast cancer, there is now a significant opportunity to correlate activity of anticancer agents with specific genetic alterations in tumors,” added Murray O. Robinson, Ph.D., senior vice president, oncology at AVEO. “Our proprietary models provide a defined genetic context in which to validate cancer gene candidates, determine their biological roles in various stages of cancer progression and test targeted therapies. We have been very encouraged by the similarity to human patients in response to widely used breast cancer agents.”

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University of British Columbia scientists have traced the fragrant scent of grapevine flowers to pollen grains stored in the anthers, contrary to common perception that petals alone produce perfume.

While studying grapes used to produce Cabernet Sauvignon from the Okanagan region of British Columbia, researchers from UBC’s Wine Research Centre and Michael Smith Laboratories identified a gene that produces and regulates fragrance from the vines’ tiny clusters of green blossoms.

“This was a surprise in fundamental plant biology,” says Joerg Bohlmann, a Distinguished University Scholar and professor in the Michael Smith Laboratories who directed the study. “This discovery gives us strong clues to the origin and evolution of fragrant flowers.”

Details of the study are published in this week’s Proceedings of the National Academy of Sciences Online Early Edition.

Scientists believe plants have evolved to produce perfume in order to attract specific types of pollinators while fending off herbivores and pathogens.

“If you ask people where the perfume of a flower comes from, they’ll likely say the female parts or the petals,” says Bohlmann. While flowers such as roses and snapdragons rely on their petals to produce perfume and attract insects, few other species have been so closely studied.

“Cultivated grapevines are largely self-pollinated, so we believe the fragrance serves more as a defense mechanism to protect their male reproductive tissues from predatory insects,” says Bohlmann, who adds that further studies on other flowering species may turn up similar mechanisms. “It may be more prevalent than we think.”

The team also found that emission of perfume is light-dependent and is strongest at dawn, possibly to coincide with pollination and predation activities.

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