Glow, Little E. Coli: Making Luminous Bacteria

A team of Michigan Technological University researchers led by Associate Professor of Chemistry Haiying Liu has discovered how to make a strain of E. coli glow under fluorescent light. The technique could eventually be used to track down all sorts of pathogens and even help in the fight against breast cancer.

E. coli bacteria are naturally found in animal intestines and are usually harmless. But when virulent strains contaminate food, like spinach or peanuts, they can cause serious illness and even death.

The researchers' trick takes advantage of E. coli's affinity for the sugar mannose. Liu's team attached mannose molecules to specially engineered fluorescent polymers and stirred them into a container of water swimming with E. coli. Microscopic hairs on the bacteria, called pili, hooked onto the mannose molecules like Velcro, effectively coating the bacteria with the polymers.

Then the researchers shined white light onto E. coli colonies growing in the solution. The bugs lit up like blue fireflies. "They became very colorful and easy to see under a microscope," said Liu.

The technique could be adapted to identify a wide array of pathogens by mixing and matching from a library of different sugars and polymers that fluoresce different colors under different frequencies of light. If blue means E. coli, fuchsia could one day mean influenza.

With funding from a Small Business Innovation Research grant from the National Institutes of Health, Liu is adapting the technique to combat breast cancer. Instead of mannose, he plans to link the fluorescent polymers to a peptide that homes in on cancer cells.

Once introduced to the vascular system, the polymers would travel through the body and stick to tumor cells. Then, illuminated by a type of infrared light that shines through human tissue, the polymers would glow, providing a beacon to pinpoint the location of the malignant cells.

The technique would allow surgeons to easily identify and remove malignant cells while minimizing damage to healthy tissue.

http://www.sciencedaily.com/releases/2009/03/090305170601.htm

EARTH HOUR

THIS IS THE WORLD’S FIRST GLOBAL ELECTION, BETWEEN EARTH AND GLOBAL WARMING

On March 28 you can VOTE EARTH by switching off your lights for one hour.Or you can vote global warming by leaving your lights on.

The results of the election are being presented at the Global Climate Change Conference in Copenhagen 2009. We want one billion votes for Earth, to tell world leaders that we have to take action against global warming.

To get involved, all you need to do is: 1. Go to the site - www.voteearth2009.org 2. Register with Friend Connect 3. Send to a friend and get more people to sign up. It would be great if you could help getting more people involved. Thanks for your help.

VOTE EARTH, BECAUSE EVERY VOTE COUNTS

Pls vote at http://www.voteearth2009.org/

FROM STEM CELLS TO NEW ORGANS

A new report brings bioengineered organs a step closer, as scientists from Stanford and New York University Langone Medical Center describe how they were able to use a "scaffolding" material extracted from the groin area of mice on which stem cells from blood, fat, and bone marrow grew. This advance clears two major hurdles to bioengineered replacement organs, namely a matrix on which stem cells can form a three-dimensional organ and transplant rejection.

"The ability to provide stem cells with a scaffold to grow and differentiate into mature cells could revolutionize the field of organ transplantation," said Geoffrey Gurtner, M.D., Associate Professor of Surgery at Stanford University and a senior researcher involved in the work.
To make this advance, Gurtner and colleagues first had to demonstrate that expendable pieces of tissue (called "free flaps") could be sustained in the laboratory. To do this, they harvested a piece of tissue containing blood vessels, fat, and skin from the groin area of rats and used a bioreactor to provide nutrients and oxygen to keep it alive. Then, they seeded the extracted tissue with stem cells before it was implanted back into the animal.

Once the tissue was back in the mice, the stem cells continued to grow on their own and the implant was not rejected. This suggests that if the stem cells had been coaxed into becoming an organ, the organ would have "taken hold" in the animal's body. In addition to engineering the stem cells to form a specific organ around the extracted tissue, they also could be engineered to express specific proteins which allows for even greater potential uses of this technology.

"Myth has its lures, but so does modern science. The notion of using one tissue as the scaffold for another is as old as the Birth of Venus to the Book of Genesis," said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal. "Eve may or may not have been formed from Adam's rib, but these experiments show exactly how stem cell techniques can be used to turn one's own tissue into newly-formed, architecturally-sound organs."

Why Hair Turns Gray Is No Longer A Gray Area: Our Hair Bleaches Itself As We Grow Older

Going gray is caused by a massive build up of hydrogen peroxide due to wear and tear of our hair follicles. The peroxide winds up blocking the normal synthesis of melanin, our hair's natural pigment.

"Not only blondes change their hair color with hydrogen peroxide," said Gerald Weissmann, MD, Editor-in-Chief of The FASEB Journal. "All of our hair cells make a tiny bit of hydrogen peroxide, but as we get older, this little bit becomes a lot. We bleach our hair pigment from within, and our hair turns gray and then white. This research, however, is an important first step to get at the root of the problem, so to speak."

The researchers made this discovery by examining cell cultures of human hair follicles. They found that the build up of hydrogen peroxide was caused by a reduction of an enzyme that breaks up hydrogen peroxide into water and oxygen (catalase). They also discovered that hair follicles could not repair the damage caused by the hydrogen peroxide because of low levels of enzymes that normally serve this function (MSR A and B). Further complicating matters, the high levels of hydrogen peroxide and low levels of MSR A and B, disrupt the formation of an enzyme (tyrosinase) that leads to the production of melanin in hair follicles. Melanin is the pigment responsible for hair color, skin color, and eye color. The researchers speculate that a similar breakdown in the skin could be the root cause of vitiligo.

"As any blue-haired lady will attest, sometimes hair dyes don't quite work as anticipated," Weissmann added. "This study is a prime example of how basic research in biology can benefit us in ways never imagined."

New Test May Help To Ensure That Dengue Vaccines Do No Harm

As vaccines against a virus that infects 100 million people annually reach late-stage clinical trials this year, researchers have developed a test to better predict whether a given vaccine candidate should protect patients from the infection, or in some cases, make it more dangerous, according to an article just published in the journal Clinical and Vaccine Immunology.

Cases of tropical, mosquito-borne dengue fever have expanding globally for more than 50 years, with nearly a third of the human population in 100 countries now at risk of infection with the four types of dengue virus. Infection with the dengue flavivirus, which is related to West Nile Virus and Yellow Fever, results in an estimated 500,000 hospitalizations and 22,000 deaths, mostly among infants, each year, according to the World Health Organization. After decades of absence in the United States, experts say the disease is causing illness again along the Texas-Mexico border, and that widespread dengue infection in the continental United States is a real possibility.

A typical dengue infection confines a patient to bed for more than a week with fever and severe limb pains, but most recover. In less than five percent of cases, however, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS), often deadly complications, develop just as the fever breaks. Mostly affecting babies between five and eight months of age, DHF causes victims to vomit and pass blood in their feces and urine. If diagnosed quickly, patients respond to intensive hospital treatment and fluids, but mortality can reach 15 percent when undiagnosed. DSS comes when the infection has caused so much fluid to leak out of capillaries that there is not enough blood to supply organs. As of 2008, there were no antiviral drugs designed to treat dengue and no drug candidates in late-stage development.

"Aggressive health education and mosquito abatement programs have saved lives, but hopes for a true solution lie with vaccine design," said Xia Jin, M.D., Ph.D., associate professor in the Department of Medicine, Division of Infectious Diseases, at the University of Rochester Medical Center. "Our study shows that the new test is likely superior to the standard test in its ability to tell whether a patient's response to a vaccine is safe," said Jin, an author for the CVI paper.

Second Time Deadly

Most people, upon first exposure to any dengue virus, develop an immune response that protects them against that version of the virus for life. Unfortunately, the dengue virus, in its ancient relationship with humans, has evolved into four related but independent classes of virus called serotypes (DENV-1, DENV-2, DENV-3 and DENV-4). The frightening aspect of the disease comes with a person's second dengue infection with one of the other three dengue serotypes, which may place them at much greater risk for bleeding and shock.

In cases where simple dengue fever progresses to DHS, patients have about 100 times as much virus in their blood as seen in a mild infection. What makes the virus so much better at penetrating human cells and reproducing the second time around? Decades of research are just now providing the answer, which lies within the intricacies of the immune system designed to recognize and destroy invading organisms.

As patients attempt to fight off a dengue infection, their immune systems activate antibodies, immune proteins that lock onto certain identifying pieces of the virus to form antibody-virus complexes that flag the virus for destruction. Humans produce a vast variety of antibodies, each with a unique "business end" shaped to recognize one specific viral protein, which enables the system to react to most invaders encountered. Ideally, an infected patient produces a large amount of the type of antibody that binds most strongly to the virus and that covers the greatest amount of the viral surface area to "neutralize" the virus (takes away its ability to reproduce).

Complicating matters is a second feature of antibodies, one which is the same across all antibodies: the crystalizable fragment (Fc). The Fc is designed to bind to proteins called the Fc receptors on the surfaces of macrophages, immune cells that roam the bloodstream seeking to engulf and "dissolve" viruses and bacteria. Coated with Fc receptors, macrophages constantly stick to the Fc end of antibodies, which brings whatever the antibody has locked onto into close contact with the cells capable of destroying it. In most people infected with their first dengue serotype, antibodies bind tightly to the viral surface and escort the virus via the Fc/Fc receptor link to macrophages where the virus is destroyed. The immune system then stores away a few of the successful antibodies in case that same virus is ever encountered again. When the system encounters a second dengue serotype, however, the antibodies from the first infection do not attach as securely to the new version in many cases, enabling the virus to break away from its antibody partner and begin copying itself. In this scenario, the antibody's Fc/Fc receptor interaction has served only to deliver the virus into cells that it could not otherwise penetrate.

The latter phenomenon, called antibody-dependent enhancement (ADE), has delayed the development of dengue vaccines for decades. The threat of enhancement dictates that any dengue vaccine must raise protective immunity against all four dengue serotypes simultaneously and equally, and several vaccine candidates have generated unequal responses across serotypes. That creates the possibility that some of the antibodies created by such vaccines could raise the risk for hemorrhagic fever and shock, and calls for the development of tests that can precisely measure enhancement risk.

Different versions of dengue move around the globe, sometimes displacing each other. Asian serotype DENV-2 strains, for example, have been taking the place of relatively more benign American DENV-2. One important example of this was seen in 1981, when Asian DENV-2 struck Cuba with nearly 900 people hospitalized following an uneventful DENV-1 outbreak four years earlier. While the Cuba outbreak followed the standard pattern, with a spike in serious cases accompanying a second infection, another outbreak, in Iquitos, Peru, in 1995, was unusual. In an area infected with DENV-1 four years previously, the second infection in 1995 with DENV-2 outbreak did not cause fatal complications. The reasons why one DENV 2 strain caused fatal second infections, and another did not, remained a mystery for years.

The current study may have helped solve the mystery, while pointing out a weakness of the standard test of antibody responses. The assay used originally to analyze the blood of patients in Iquitos was the plaque-reduction neutralization test (PRNT), the recognized gold standard for determining how effectively the human immune system responds to dengue infection. PRNT starts with a sheet of cells chosen because they can be invaded by the virus, and because they share some qualities with the kind of cell targeted by the virus in the body, the macrophage.

When the viral strain being studied is introduced to this cell culture, it begins invading and killing the cells, and making copies of itself. By diluting these mixtures, scientists can identify and count "islands" (or plaques) in the culture where the virus has destroyed cells.

When serum (which contains antibodies) from an infected patient's blood is added to this mix, the number of spots over time reveals the degree to which the patient's antibodies can effectively neutralize the virus. In the case of dengue research, PRNT tests are used to measure how efficiently the antibodies from a natural infection protect the cultured cells from the experimental infection with a second dengue serotype.

According to past experiments on the standard PRNT test, it took on average about seven times as many antibodies created by DENV-1 infection to neutralize Asian DENV-2 vs. American DENV-2. Jin and colleagues added an important element to the PRNT test, and then retested the Iquitos samples. The new, more sensitive test found that it took up to 100 times as many DENV-1 antibodies to neutralize the Asian DENV-2 virus as it did to the American DENV-2 infection. The results suggest that, in the harmless Iquitos outbreak, the second dengue serotype to hit the region was the American version of DENV-2, was cross-neutralized with relative ease by antibodies created by the first infection. In Cuba, however, the people were unfortunate to be hit by the Asian DENV-2 upon second infection, which their antibodies from DENV-1 infection could not shut it down, and only helped to deliver the virus into their cells. By magnifying the differences in the ability of an antibody for a given dengue serotype to neutralize other serotypes, researchers believe the new test will capture enhancement that the older test misses.

To construct the new test of cross-neutralization, researchers took CV-1 fibroblast cells, which share some traits with macrophages, and genetically engineered them to include a gene that directs for the building of an FC receptor on their surfaces. They also constructed a CV-1 cell line for culture without Fc receptors for use as a control group that resembles standard PRNT cultures used in the past. Both sets of cultures were then subjected the blood taken from patients in the 1995 Peru outbreak, and the new test captured for the first time the contribution of antibodies to more severe disease via fc/fc receptor delivery of virus to target cells.

Along with Jin, the work in Rochester was led by corresponding author Jacob Schlesinger, M.D., and Robert Rose, Ph.D., as well as by graduate student W. W. Shanaka I. Rodrigo, who conducted the genetic engineering experiments on CV-1 cells. Also contributing in Rochester were Danielle Alcena and Zhihua Kou. Tadeusz Kochel contributed from at the Naval Medical Research Center Detachment, Lima, Peru, as did Kevin Porter at the US Naval Medical Research Center, Silver Spring, Maryland. Guillermo Comach led a team as well at the Laboratorio Regional de Diagnostico e Investigacion del Dengue y otras Enfermedades Virales in Maracay Estado Aragua, Venezuela.

"Beyond the Peruvian case, our test promises to have a profound effect on the design of vaccines because we can take the antibodies generated by two different candidate vaccines, and better compare which strongly neutralizes virus without threat of enhancement across all four serotypes," Jin said. "With experimental vaccines from companies like GlaxoSmithKline and Sanofi Aventis entering Phase II and Phase III clinical trials this year, we hope the new test will be adopted widely and soon because it is more likely to catch enhancement."

Stem Cells From Skin Cells Can Make Beating Heart Muscle Cells

In a study published online Feb. 12 in Circulation Research, UW-Madison School of Medicine and Public Health professor of medicine Tim Kamp and his research team showed that they were able to grow working heart-muscle cells (cardiomyocytes) from induced pluripotent stem cells, known as iPS cells.

The heart cells were originally reprogrammed from human skin cells by James Thomson and Junying Yu, two of Kamp's co-authors on the study.

"It's an encouraging result because it shows that those cells will be useful for research and may someday be useful in therapy,'' said Kamp, who is also a cardiologist with UW Health. "If you have a heart failure patient who is in dire straits — and there are never enough donor hearts for transplantation — we may be able to make heart cells from the patient's skin cells, and use them to repair heart muscle. That's pretty exciting."

It's also a few more discoveries away. The researchers used a virus to insert four transcription factors into the genes of the skin cell, reprogramming it back to an embryo-like state. Because the virus is taken up by the new cell, there is a possibility it eventually could cause cancer, so therapies from reprogrammed skin cells will likely have to wait until new methods are perfected.
Still, the iPS cardiomyocytes should prove immediately useful for research. And Kamp said the speed at which knowledge is progressing is very encouraging.

Jianhua Zhang, lead author on the study, noted that it took 17 years, from when a mouse embryonic stem cells were first created in 1981, to 1998, when Thomson created the first human embryonic stem cells. In contrast, the first mouse iPS stem cells were created in 2006, and Thomson and Yu published their paper in November 2007, announcing the creation of human iPS stem cells that began as a skin cells.

While research on embryonic stem cells is controversial, because it destroys a human embryo, lessons learned through such research apply to current work with iPS cells made from adult cells.

"That's one of the important things that have come out of the research with embryonic stem cells, it taught us how human pluripotent stem cells behave and how to work with them,'' Kamp says. "Things are able to progress much more quickly thanks to all the research already done with embryonic stem cells."

Many types of heart disease have known genetic causes, so creating cardiomyocytes grown from patients who have those diseases will likely be some of the next steps in the research. One of Kamp's colleagues, Clive Svendsen, a UW-Madison School of Medicine and Public Health professor of neurology and anatomy, has grown the iPS cells into disease-specific neural cells. Kamp and Svendsen are also on the faculty of the Waisman Center and the Stem Cell and Regenerative Medicine Center.

Kamp's latest research, proving that iPS cells can become functional heart cells, is just one step along the way to better understanding and treatment of disease.
"We're excited about it, because it's the some of the first research to show it can be done, but in the future, we'll probably say, 'Well, of course it can be done,'" he says. "But you don't know until you do it. It's a very mysterious and complicated dance to get these cells to go from skin cells to stem cells to heart cells."

Wrinkles Removed With Protein RHAMM

Hollywood stars of a certain age take note: Research at Berkeley Lab suggests that a protein linked to the spread of several major human cancers may also hold great potential for the elimination of wrinkles and the rejuvenation of the skin. If this promise bears fruit, controlling concentrations of the RHAMM protein could one day replace surgical procedures or injections with neurotoxins that carry such unpleasant side-effects as muscle paralysis and loss of facial expressions.

RHAMM stands for Receptor for Hyaluronan Mediated Motility. Mina Bissell, a cell biologist with Berkeley Lab’s Life Sciences Division and a leading authority on breast cancer, was collaborating with Eva Turley, an oncology professor at the University of Western Ontario and leading authority on tissue polysaccharides, on a study of the role that RHAMM plays in regulating the signaling of adipocytes (fat cells) during the repairing of tissue wounds from injuries such as skin cuts, heart attacks and stroke. Earlier research by Turley, who discovered RHAMM, had shown that over-expression of this protein points to a poor patient outcome for such human cancers as breast, colon, rectal and stomach.

In the course of their collaborative study, Bissell and Turley, working with mice, discovered that blocking the expression of the RHAMM protein - either by deleting its gene, or through the introduction of a blocking reagent - can be used to selectively induce the generation of fat cells to replace those lost in the aging process. At the same time blocking RHAMM expression also reduces deposits of unhealthy visceral fat.

“This technique could be developed as a means of providing a non-surgical approach for normalizing skin appearance after reconstructive surgery, for wrinkle reduction, and for face lifts and figure enhancement,” said Bissell.

Said Turley, “Unlike neurotoxin agents, which have to be injected periodically, a localized injection of a RHAMM inhibitor should produce long-lasting skin volumizing effects and would not involve muscle paralysis, which means there would be no loss of expression if it were to be injected into the face.”

There are compounds now on the market that promote the production of adipocyte cells and result in increased subcutaneous fat, however, these adipocyte-promoting factors also increase the production of visceral fat. The mouse studies led by Bissell and Turley have shown that blocking RHAMM expression significantly increases subcutaneous fat while decreasing visceral fat. This suggests that blocking RHAMM should also have a beneficial effect on patients with obesity-related diseases, cardiovascular disease or diabetes. Another unique advantage of RHAMM is that its expression in normal adult human tissues is restricted.

“Therefore, anti-RHAMM agents should have low toxicity and according to preliminary animal studies, could be beneficial to patients with a tumor or inflammation-related disease,” said Turley.

Potential applications of RHAMM modulation in addition to wrinkle reduction include normalizing skin appearance after reconstructive or cosmetic surgery, e.g., grafted tissue on burn victims. It has also been shown to have a beneficial effect on tumors and inflammatory diseases in mice.