Report Outlines Benefits and Drawbacks of Genetically-Engineered Crops; Looks Toward Future

The National Research Council (NRC), a part of the National Academies, recently published a report that provides a detailed assessment of the impact of genetically-engineered (GE) crops on farmers. Genetically-engineered crops were first introduced to farm fields in 1996. Today, GE crops account for over 80 percent of the soybean, corn, and cotton grown in the United States. The majority of these GE crops are resistant to glyphosate (the active ingredient in RoundUp weedkiller) and make Bacillus thuringiensis, or Bt, a bacterium that is poisonous to the insects that eat it.
The NRC tied GE crops to a number of benefits, including:

  • lower production costs,
  • fewer pest problems,
  • reduced use of pesticides, and
  • greater crop yields.

A number of environmental benefits were also associated with GE crops. The greatest benefit was seen in terms of water quality. Due to the use of fewer pesticides and insecticides, hazardous chemical run-off is less of a problem at farms that grow genetically-engineered crops.

One worry of using these glyphosate-resistant GE crops is that problems with weeds could arise in the future as the weeds themselves become resistant to glyphosate. This resistance has already arisen in nine weed species since the introduction of GE crops. The report authors suggest that farmers utilizing GE crops should not make the crops themselves their only weed/insect management program. Instead, to maintain the crops’ effectiveness against weeds, it is suggested that farmers use an integrated weed management system that involves pesticides other than glyphosate. As to fending off insect pests, the NRC recommends that farmers continue to utilize EPA-mandated “refuges” in which conventional crops are grown alongside their GE crop fields. The thought behind these refuges is that the insects will opt to feed on the conventional plants and not the GE crops, thus reducing the chance of the insects becoming resistant to the inserted Bt gene.

In the report, the National Resource Council provides a number of suggestions for future studies and research. One such suggestion is to further study the impact that genetically-engineered crops have on both conventional and organic farmers. In addition, the NRC suggests that government support be made available to researchers interested in studying genetically-engineered crops that provide a public benefit, such as reduced environmental impact.

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Scientists Uncover Mystery of Flu Virus Evolution

Researchers at the University of Rochester Medical Center (URMC) have uncovered the mechanism that lets the flu virus evolve so efficiently within and between host species. In their research, the scientists found that the secret to the flu virus’s evolutionary success lies in its unique replication process. Previously, scientists thought that the flu virus evolved so quickly due to an error-prone replication process. However, this new research refutes that hypothesis. Instead, the researchers discovered that the flu virus’s unique replication process lets enough mutations form that the virus can easily spread and adapt to its host environment. In addition, this replication process allows just enough mutations to occur without causing catastrophic mutagenesis—that is, without killing itself in the process.

These new findings give us insights into how we may be able to control viral evolution,” Baek Kim, Ph.D., professor in the department of Microbiology and Immunology at UMRC and lead study author, said in a press release about the discovery. This research presents an attractive strategy for tackling the flu—making the influenza virus kill itself by amplifying the number of mutations made beyond the desired level, which is lethal for the virus.

In their study of the mechanisms behind flu virus evolution, the researchers used biochemical analysis methods to compare flu virus replication with human-immunodeficiency virus (HIV) replication. The scientists found that while the polymerases, that is, the enzymes, behind replication are quite error-prone in HIV, they are much more accurate in the flu virus. Though both viruses depend on mutations for survival, HIV is only able to replicate its genome a few times during an infection, meaning it isn’t able to produce that many mutations. In contrast, the flu virus replicates itself a number of times during an infection, and this gives it ample time to produce a huge number of mutations that allow the virus to thrive.

The results of the scientists’ research was published online in the April 29, 2010 edition of the open-access journal PLoS One. Researchers who contributed to this study included Shilpa Aggarwal, Birgit Bradel-Tretheway, Toru Takimoto, Stephen Dewhurst, and Baek Kim.

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CO2 Emissions Also a Concern in the Oceans

Though carbon dioxide (CO2) emissions are well-known as a contributor to global warming, it is not as well known that CO2 emissions also cause ocean acidification. Ocean acidity has risen 30 percent since the arrival of the Industrial Age. Research indicates that if CO2 continues to be emitted at today’s rates, it is expected that ocean acidity will increase by an additional 100 percent by the year 2100. Researchers based in Europe are currently conducting an experiment to determine how an increase in oceanic CO2 concentrations will affect oceanic organisms such as plankton.

This research project, funded by the European Union, is a multi-disciplinary affair. Among the researchers involved in this experiment are cell biologists, molecular biologists, marine ecologists, biogeochemists, and oceanic and atmospheric chemists. The scientists’ experiment is taking place off the coast of Svalbard, an island archipelago in the Arctic Sea. This oceanic experiment is the first of its kind to test the effect of increased CO2 concentrations in the Arctic Ocean. Ocean acidification is particularly worrisome in polar seas because carbon dioxide is absorbed more readily in cold water. This absorption of CO2 leads to unnaturally low carbonate saturation states in the water. This situation is particularly problematic because these sub-saturated waters could be corrosive to organisms made of calcium, such as shellfish, sea urchins, and calcareous plankton.

Many of these organisms play a key role in the oceanic food web. For example, plankton are eaten by organisms including fish, sea birds, and whales. The loss of plankton, or any other organism in the polar oceans, could have a disastrous effect on the rest of the food web.

In their six-week long experiment, the scientists have enclosed ocean plankton into nine 17-meter long “test tubes,” which each hold a volume of 50 cubic meters of seawater. Inside each “test tube,” the confined plankton are exposed to a range of CO2 concentrations that are expected to occur between now and the middle of the next century. The scientists are monitoring how these different CO2 concentrations affect the plankton, and their results should provide important information as to how increased CO2 concentrations in the ocean will affect oceanic organisms in the future.

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Learning Through Dreams

Researchers at Harvard University and Harvard Medical School conducted an experiment that indicates that dreaming during non-REM (rapid eye movement) sleep after performing a difficult task helps participants complete the activity more successfully after waking. (Scientists have only observed learning during non-REM sleep and not during REM sleep.) The researchers’ results also indicate that just thinking about the activity after first performing it does not help in later attempts to complete the task. These findings support earlier research indicating that sleep improves memory and learning.

“Task-related dreams may get triggered by the sleeping brain’s attempt to consolidate challenging new information and to figure out how to use it,” Dr. Robert Stickgold, study co-author, told ScienceNews about their results.

Researchers recruited 99 college students between the ages of 18 and 30 to participate in the study. For the experiment, the volunteers spent 60 minutes working individually to solve a 3-D virtual maze on a computer. During the activity, the participants performed several trials, and started the maze at a different location each time. In addition, while solving the maze, the participants were told to memorize the location of a specific tree’s location in the puzzle.

After spending an hour working on the maze, the participants were given a five-hour break. Half of the participants were instructed to take a nap, and the other half of participants were told to take part in quiet activities, such as reading or watching a video. For the nap group, the researchers fitted each participant with scalp sensors to monitor their brain activity while asleep. In addition, members of the napping group were asked about the content of their dreams just before they fell asleep, one minute after non-REM sleep, and at the end of their nap. Of the 50 participants in the nap group, four recounted dreaming about the maze activity. For the participants in the quiet activity group, each members was asked what they were thinking about at the beginning, middle, and end of the activity period.

After a lunch break and another period of quiet activity in which both groups of participants took part, the volunteers were asked to repeat the virtual maze activity. Those participants in the nap group who recalled dreaming about the maze in their sleep performed better the second time around in the maze activity and also found the tree that they had been told to remember quicker than other participants. All of the members of the nap group had been relatively unsuccessful in their attempts to complete the maze in the earlier session. The study authors suggest that tasks that are difficult and/or important to complete provoke memory processes in the brain required for learning to activate during sleep.

The scientists plan to continue their research into the connection between dreaming and learning. Future research plans include having study participants navigate through a more “exciting” virtual maze. The researchers are also interested in determining whether participants that have REM dreams about the maze during a normal full night’s sleep are able to better navigate the maze the next day.

The results of the scientists’ research were published in the April 22, 2010 online edition of the journal Current Biology. Study authors included Erin J. Wamsley, Matthew Tucker, Jessica D. Payne, Joseph A. Benavides, and Robert Stickgold.

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Gram-Negative Bacteria May Be the Next Big Threat

Though MRSA gets all the press, scientists find the rise in cases of hospital-based infections by Gram-negative bacteria worrying. Though incidences of infection by these bacteria currently occur at much lower rates than incidences of MRSA infections, those in the medical profession are concerned by the lack of drugs able to combat the infections by Gram-negative bacteria that do occur.

Although there currently exist drugs to combat MRSA infections, there are hardly any antibiotics that can fight an infection by Gram-negative bacteria. If a severe infection does occur, doctors must rely on only two drugs&mdah;developed in the 1940s—that were taken off the market decades ago due to concerns about nerve and kidney damage. Because MRSA infections occur at a much higher rate and are not confined to hospitals, as Gram-negative bacteria-based infections currently are, the pharmaceutical industry has focused their research on drugs to combat MRSA infections. One obstacle pharmaceutical companies must overcome is that Gram-negative bacteria infections are particularly hard to fight with antibiotics due to the configuration of the bacteria’s cell structures.

In the United States, the Centers for Disease Control (CDC) indicate that of the 1.7 million hospital-based bacteria infections that occur each year, 99,000 result in death. In Europe, it is calculated that two-thirds of the 25,000 deaths per year caused by hospital-based bacterial infections can be attributed to Gram-negative bacteria.

Though infections by Gram-negative bacteria have mostly remained under the radar, pharmaceutical companies and medical researchers are beginning to take action. Earlier this year, researchers at a Swiss biotech company called Polyphor and scientists at the University of Zurich announced they had developed a new class of antibiotics to fight infections by Gram-negative bacteria.
These antibiotics effectively work by deactivating a protein necessary for the formation of the bacteria’s outer cell membrane. Continued breakthroughs such as this provide hope that Gram-negative bacteria infections may not end up being the public health nightmare that MRSA has in some cases become.

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Investigating How Consent Forms Have Changed Over Time

Signed consent forms are a necessary part of scientific research that uses human subjects. These consent forms typically inform potential subjects about the purpose of the study, risks and benefits of their involvement, the length of time involved, payment amount (if any), and a description of their rights. Because of problems in the past with regard to adequately informing potential subjects about every aspect of a study, including its potential risks and how the collected data will be used, today consent forms are standardized and guided by strict regulations.

Researchers at the University of Pennsylvania Law School and Columbia University recently conducted a study of how consent forms have changed over a 25-year time period. The researchers specifically looked at consent forms that were used between the years 1978 and 2002. Their study resulted in two main findings. They found that, over time

  • consent forms have become more accurate, and
  • consent forms have grown substantially in length, from just a few paragraphs to over four pages in length.

Though the researchers find it quite heartening that the amount of discrepancies and/or inaccuracies in consent forms have dropped drastically, they find it worrisome that consent form length has increased dramatically. According to the study authors, data suggests that “consent forms longer than 1,000 words (four double-spaced pages) are unlikely to be read, perhaps in part because of the time involved.” Research indicates that consent forms should be limited to 1250 words or less (that is, no more than five pages) and the information should also be presented in other ways, such as through an informational booklet that potential subjects can read on their own time or through video or computer-based disclosures. Research also indicates that consent forms could be shortened by including only the most pertinent information that potential subjects would need to know in deciding whether or not to take part in the research study.

The results of the researchers’ study were reported in the May-June edition of the journal IBS: Ethics & Human Research. Study authors included Ilene Albala, Margaret Doyle, and Paul S. Appelbaum.

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Stem Cells Isolated From Surgery Leftovers

Scientists at England’s University of Bristol have extracted stem cells from sections of vein removed for heart bypass surgery. Their research indicates that these stem cells can stimulate new blood vessel growth—meaning they could be useful in repairing heart tissue damaged during a heart attack. Dr. Paolo Madeddu, Professor of Experimental Cardiovascular Medicine and his research team in the Bristol Heart Institute (BHI) at the University of Bristol recently published the results of their research in the journal Circulation.

“This is the first time that anyone has been able to extract stem cells from sections of vein left over from heart bypass operations,” Dr. Paolo Madeddu said in a press release published by the university. “These cells might make it possible for a person having a bypass to also receive a heart treatment using their body’s own stem cells.”

During heart bypass surgery, surgeons remove a portion of a patient’s leg vein. This vein is then grafted onto the blocked or narrowing coronary artery and helps restore blood flow to the heart. During the procedure, surgeons typically remove a longer length of leg vein than is needed.

In their research, scientists isolated stem cells from the leftover veins donated by heart bypass patients. The researchers inserted these stem cells into mice and were able to stimulate new blood vessel growth in injured leg muscles.

Repairing a damaged heart is the holy grail for heart patients,” Professor Peter Weissberg, Medical Director of the British Heart Foundation, stated in the press release. “The discovery that cells taken from patients own blood vessels may be able to stimulate new blood vessels to grow in damaged tissues is a very encouraging and important advance. It brings the possibility of cell therapy for damaged hearts one step closer and, importantly, if the chemical messages produced by the cells can be identified, it is possible that drugs could be developed to achieve the same end.

Funding for this research was provided by the British Heart Foundation.

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Delivering Vaccines Through Reengineered Food Poisoning Microbes

Researchers based at the Monash Institute of Pharmaceutical Sciences located at Monash University in Melbourne, Australia have discovered a way to deliver a vaccine orally with the help of a genetically engineered harmless version of the dangerous bacteria Listeria monocytogenes.

L. monocytogenes lives in soil and water. Foods such as fruits or vegetables may become contaminated with Listeria from the soil. Food from animal sources, such as meat or dairy products, may become contaminated from infected animals (which often show no symptoms of infection). If present, the Listeria bacterium is normally killed during the pasteurization process or cooking. However, improper food handling following processing can result in L. monocytogenes contamination.

Contamination by L. monocytogenes results in the food-borne illness called listeriosis. Symptoms of listeriosis include fever, muscle aches, and gastrointestinal conditions such as nausea or diarrhea. Listeriosis can also spread into the nervous system, leading to headaches, confusion, stiff neck, loss of balance, or convulsions. Those most susceptible to Listeria infections include pregnant women, infants, the elderly, and those with compromised immune systems.

Listeria is effective because it is able to survive the harsh, acidic conditions of the stomach and, using a protein called invasin, is able to penetrate epithelial host cells in the gastrointestinal tract. Colin Pouton and his colleagues at Monash University exploited this characteristic in developing their oral vaccine using a modified L. monocytogenes as the carrier. Oral vaccines are typically not effective because they are destroyed by stomach acid; since this is not a problem for the Listeria bacterium, this quality makes Listeria an excellent way to transport a vaccine.

In their research, the scientists created a new strain of L. monocytogenes that rendered the bacteria harmless and could instead by packed full of medicine or a vaccine. The thought was that the modified Listeria bacterium could be used to infect the recipient with a beneficial vaccine. The scientists also made the new strain of L. monocytogenes suicidal, meaning that the bacteria burst and die after entering the host cells.

In a trial run using intestinal cells grown in the lab, the scientists showed that the modified Listeria strain was able to successfully infiltrate the cells, deliver the intended protein, and then die, causing no harm to the intestinal cells themselves. Though encouraged by these early findings, more research will be necessary before this oral vaccination can be used in human subjects.

The results of the scientists research were published in the journal Molecular Pharmaceutics. Scientists who contributed to this research include Cheng-Yi Kuo, Shubhra Sinha, Jalal A. Jazayeri, and Colin W. Pouton.

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Researchers Find H1N1 Flu Virus Able To Infect Lung Cells

The H1N1 flu virus. (Photo credit: C. S. Goldsmith and A. Balish / CDC)

The H1N1 flu virus. (Photo credit: C. S. Goldsmith and A. Balish / CDC)

Researchers at Imperial College London have determined that, unlike the seasonal flu, the H1N1 flu virus is able to infect cells deep within the lungs, which potentially can lead to serious lung infections. The scientists believe this is one reason why H1N1 fly infections commonly have more severe symptoms than seasonal flu infections.

In their research, the scientists used a method called a carbohydrate microarray to determine to which receptors the two different viruses are able to connect. In this method, a glass surface was covered with 86 different receptors. The researchers then added the viruses to the glass surface. A “lit up” surface indicated that a virus was able to bind with a receptor.

Like most viruses, the flu virus infects cells by attaching to receptors on the outside of the cell. After connecting to a cell, the virus enters the cell and takes over the cell’s functions and manufactures more copies of the virus. The cell then lyses (bursts), and the new virus copies infect nearby cells, continuing the process. The seasonal flu virus is able to infect (that is, attach onto receptors on) cells in the nose, throat, and upper airway of the respiratory system. The H1Ni flu virus is also able to attach to cells in these same areas. However, in contrast, to the seasonal flu virus, the H1N1 virus can also attach onto cell receptors located deep in the lungs.

The researchers discovered that the H1N1 virus’s attachment to cells in the lungs is a weak bond. They think this is one reason why not everyone who is infected by the virus experience severe lung problems. However, the scientists worry that a mutation could make the virus better able to attach to receptors in the lungs, leading to more cases of severe lung infections.

Results of the scientists’ research was published in the September 2009 issue of the journal Nature Biotechnology. The research was funded in part by the Wellcome Trust, the Medical Research Council, and the Engineering and Physical Sciences Research Council.

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Scientists Develop Iron-Rich Rice Plant

Iron deficiency can be a problem for those who do not eat a well-balanced diet, and it can be an especially insidious problem for populations in developing countries. Women and children are particularly vulnerable to iron deficiency. Symptoms of iron deficiency include pronounced fatigue and an inability to metabolize certain harmful substances. Iron deficiency can lead to anemia, which is a condition in which the body does not produce enough healthy red bloods necessary to transport oxygen to the body’s tissues. In many developing countries, one of the major food sources (and sometimes only food source) is rice. Rice, in its unaltered form, is actually a good source of iron. However, most rice provided to populations in developing countries is peeled rice; that is, the seed coat has been removed. The seed coat is often removed to give the rice a longer shelf life; rice that retains its seed coat is likely to spoil faster in sub-tropical and tropical climates typically found in developing countries.

Because iron supplements or other food sources are not readily available or overly expensive, scientists are working on developing an iron-rich variety of rice. Researchers at the Swiss Federal Institute of Technology Zurich (also referred to as ETH Zurich) have had success in doing just that.

Lead researchers Christof Sautter and Wilhelm Gruissem worked with colleagues to genetically modify a rice plant to increase its iron content. In their experiment, the scientists inserted two plant genes into an existing variety of rice. The two inserted plant genes work together to both mobilize and store iron. In addition, the inserted genes aid in the rice plant’s ability to absorb a greater quantity of iron from the soil and also store more iron in the rice kernel. Most importantly, the modified rice plant was shown to have a six-fold increase in iron content compared to a typical (unmodified) rice plant.

More research and experiments, including tests to see whether the modified rice plants will grow under typical agricultural conditions, are necessary before the modified rice plants will be available commercially. Regulations require that genetically-modified seeds and plants must undergo a rigorous period of greenhouse and field testing to ensure that it is safe for human consumption and will not have negative impacts on an ecosystem. In addition, the scientists are interested in increasing the modified rice plant’s iron content to at least twelve-fold; that is, twice the level they currently have achieved. Upon the modified rice plants eventual assumed approval, the scientists would like to provide it to small-scale and self-sufficient farmers at no cost, given the crop’s humanitarian implications.

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