Concerns of pesticide use on produce has raised questions to some of the population because of new studies showing linkage to certain diseases. As a result, some seek organic products at the grocery store. Another alternative is purchasing fresh produce at the farmer’s market which has become popular in recent years. The general population believes that locally grown foods are safer. However, that might not be the case in a small-scale study conducted by Penn State’s College of Agricultural Science.
Food safety is of utmost importance to the satisfaction and health of consumers, and control of microbial growth is a key factor to preventing food spoilage. An Australian study, performed by the Food Safety and Innovation Research and Development Institute took a look at the effects of various types of packaging techniques on the longevity of storage in lamb shoulders.
A novel class of antibiotic being explored at the University of Adelaide has shown potential in the fight against bacterial antibiotic resistance. Professor Andrew Abell and his colleagues have engineered antibiotic compounds that target a key metabolic enzyme, biotin protein ligase, instead of the cell membrane, which is a common target of some existing antibiotics. By changing the target of the antibiotic, it is hoped that a broad range of antibiotic resistant bacteria will again be susceptible.
The harlequin ladybird Harmonia axyridis, one of the world’s most invasive insects, has become an invader of Europe and North America. Initially introduced for biological pest control, the harlequin ladybird, native to Asia, is now harming indigenous ladybird species, specifically the seven-spotted ladybird Coccinella septempunctata. Previously, some scientists believed the harlequin’s success was due to a harmonine, a toxic antibacterial chemical found in its blood. However, entomologist Andreas Vilcinskas of Justus-Liebig-University in Giessen, Germany believes the harlequin’s success is partly due to the presence of a single-celled parasite.
Today, there is an epidemic in the United States that was not apparent 50 years ago. This epidemic is obesity amongst adults and children in this country. Blame for obesity has been set upon processed foods and sedentary lifestyles, but it wasn’t until Eiji Hara of Tokyo turned his attention towards microbes in the intestine that other significant factors were considered to be risks of obesity as well.
Hara executed two types of experiments. In one experiment, he fed mice different diets to make them obese or lean, but each group was still exposed to a carcinogen. In another experiment, he focused on mice genetically susceptible to being obese even while fed a normal diet.
Scientists have found, to their surprise, that after two and a half years of being antibiotic free, pigs that were involved in a Canadian study carried bacteria that were still resistant to antibiotics. Scientists originally hypothesized that the antibiotic resistant mutation would be associated with some sort of fitness disadvantage, like many similar mutations. If this had been true, the bacteria would have been likely to lose their resistance when no longer in the presence of antibiotics.
Recent studies conducted at the University Of Maryland School Of Medicine indicate that bacterial DNA can be transferred to human tumor cells easier than into healthy human cells. Such genetic transfer, in which DNA from one organism is implemented into another organism of a different species, without traditional reproduction processes, is called lateral gene transfer or horizontal gene transfer.
In order to research the role of lateral gene transfer in tumors, researchers at the University of Maryland Marlene and Stewart Greenebaum Cancer Center are using a specific strategy involving large quantities of samples, both cancerous and non-cancerous. This strategy was invoked by The Cancer Genome Atlas (TCGA). Scientists at the University of Maryland found that 63.5 percent of the TCGA samples that they studied were from tumors. Interestingly, 99.9 percent of the tumor samples contained evidence of bacterial gene transfer.
It isn't often when scientists and policy makers think about the effects of climate change that they consider the microbial population. Microbes are 60% of the biomass on earth and have profound effects on the global environment. As a demonstration of this, Professor Ferran Garcia-Pichel of Arizona State University has studied the microbes present in desert soil using new molecular survey techniques. These methods allow researchers to rapidly characterize the population of microbes present.
In the research field, regulation of DNA replication during the initiation phase is well known while very little is known about regulation of replication during the elongation period. The process of DNA replication is complex, and it is highly regulated by specific factors in the environment. One factor that impacts regulation is the abundance of nutrients in the cell. In the bacterium Bacillus subtilis, replication elongation is inhibited when the cell undergoes amino acid starvation. In the bacterium Escherichia coli, the same effect of amino acid starvation on the cell is observed as well.
Balnca Bernal and William Mitsch have just published a paper in the Journal of Environmental Quality that looks at the potential of wet lands to serve as carbon sinks. Their paper shows that wetlands accumulate 242 g of carbon m-2 yr-1. This is 70% more than a natural wetland. Wetlands are great at trapping carbon because when plants that grow in the shallow water die, they fall into the water and must be degraded anaerobically. This is a much slower process, and a significant fraction of the carbon may not be degraded for thousands of years. Wet lands are also a great way for farmers to prevent farm runoff, purify the water and provide habitat for wildlife. You can also read a press release about the research.
Researches at the Univ. of Mass-Amhearst, lead by professor Dan Chase have developed a technique that allows the down regulation of any protein, at any time, without mutation of the DNA of the organism under study. This will allow scientists to remove a protein activity in just one cell, and not affect the metabolism of the entire organism. Dr. Chase's team used this technique to determine what would happen if they manipulated dopamine levels in the worm Caenorhabditis elegans. This worm is a fantastic model system to study development and all sorts of eukaryotic functions. It contains only 959 cells, yet carries out many of the functions of more complex organisms, including humans.
Obesity in this country is reaching epidemic proportions. Over 30% of the United States adult population is obese. This is not genetics. Thirty years ago we did not near the number of obese adults as we do today. It is a matter of poor diet and lack of exercise. To add to this phenomenon, research by Dr. Elizabeth Thomas demonstrates that skipping breakfast, just once, can cause acute insulin resistance. In this condition, the body requires higher levels of insulin to cause cells to absorb the glucose in the blood stream and lower glucose levels into a normal, healthy range. Even worse, making a habit of skipping breakfast can lead to chronic insulin resistance, thus increasing an individuals risk for type 2 diabetes.
The best thing you can do to keep your weight at a healthy level is to eat the appropriate number of calories and, just as important, eat at regular intervals.
A team of researchers at the University of Iowa, lead by Marin Schweizer, have developed guidelines that could reduce the incidence of post-surgery infections by more than 70%. The sources of post-operative infection in 85% of cases originated with the patient. They were infecting themselves, sometimes with highly resistant microbes, such as MRSA. These microbes were found to be harbored in the nasal passages and the patients would transmit the microbe by touching their nose and then the wound. The protocol for this procedure is very simple,
- Swab patients’ noses looking for both MRSA staph and those that are sensitive to methicillin before surgery
- For the 30 percent of patients who have staph naturally in their noses, apply an anti-bacterial nose ointment in the days before surgery
- At surgery, give an antibiotic specifically for MRSA to patients who have the MRSA strain in their noses; for all others, give a more general antibiotic
The researchers are now conducting a study at 20 community hospitals nationwide to test its effectiveness. Judging from past, similar interventions, this should be successful. Interestingly, the study reported that 47% of hospitals do not use nose ointment before surgeries. Staph infections are extremely dangerous, and drug resistant strains, such as MRSA, can be nearly impossible to control.
Dr Michael Shaw and his team at the CDC are making rapid progress in understanding the H7N9 influenza virus that is causing lethal cases of flu in China. There is great concern about this virus, and its potential to cause a serious pandemic. Currently the virus is not transmitting readily human-to-human, with most cases being bird-to-human. Unfortunately, the virus does not seem to greatly sicken birds, making it harder to detect and easier to spread. You can find some cool graphics and images of influenza at the CDC
Saleh Heneidi et al at UCLA have reported in PLOS One the isolation of pluripotent stem cells from adult adipose (fat) tissue. By stressing the tissue they killed off all of the cells in the fat tissue except the Multilineage Differentiating Stress-Enduring (Muse) Cells. These cells behave in cell culture in a manner reminiscent of embryonic stem cells and tests reveal that they can differentiate into mesenchymal, endodermal and ectodermal cell lineages. It is clear that these are very primal cells and hold the potential of making any type of tissue. This is clearly a very exciting step.
An interesting side note to the article, these were discovered by accident when a piece of equipment failed in the lab, killing most of the cells in the cell culture, but leaving the Multilineage Differentiating Stress-Enduring (Muse) Cells alive.
The process of creating the 5th edition of Through the Microscope has begun and you are at the new site. Unlike typical publishers, the process is completely open and you can watch the book take shape. Here is what is coming in the new edition
- Upgrade the backend server software to the latest release of Zikula.
- Create a new look for the book
- Update Microbial Diversity
- Update Microbial Ecology
- Update Bacterial Structure
The deadline for the 5th edition is August 2013.
An international team of scienctists has worked out a new biosensor that is able to detect its target molecule over a large concentration range. This will make these sensors more useful in many different applications; drug detection, cancer screenings, cancer treatment, and infectious disease. The method can detect its target in seconds.
The results are in, calorie restriction may not extend your life. Previous studies of rats and mice demonstrated that calorie restriction could extend life span. While human behavior can sometimes be rat-like, there are distinct differences in physiology between rats and humans. A much anticipated calorie restriction study using rhesus monkeys shows that these results do not translate to our close cousins. Being overweight is a tremendously important predictor of life expectancy, but the number of calories you consume, if you are still thin, does not appear to make a difference in this study.
Jeffrey D. Karpicke and Janell R. Blunt report that using tests to measure your comprehension of a subject also has the side benefit of helping you remember the material better. The NY times has an excellent article summarizing the findings.
Through the Microscope has dozens of concept quizzes throughout the text that help you to check your understanding of the material. Each chapter also has an end of chapter quiz to further cement the concepts. As you use this text, make sure you take advantage of theses tools.
Cornell Professor Lawrence M. Cathles who studies Earth sciences calculates that switching from coal and oil to natural gas as we move toward renewable energy could decrease carbon emissions significantly. We do need a transition period, but lets make it as short as possible.
Malaria is the most important tropical disease in the world, with over 665,000 deaths worldwide, many of them in children. The malaria parasites, protozoa of the Plasmodium genus, are susceptible to a number of drugs, but have been becoming more resistant the drugs available for treatment. Professor Jonathan Vennerstrom of the University of Nebraska Medical Center College of Pharmacy and his team announce the development of Synriam (a synthetic trioxolane) that has many of the properties of artemisinin, but none of the downsides.
The paper describing the synthesis, toxicology, and effectiveness of this trioxolane is available in Nature. I found it was interesting that this paper was published in 2004, yet the clinical trials took 8 years to complete and bring this drug to market. It demonstrates how careful governments have to be with new drugs being introduced into the market.
Floc is a real work, even if your spell-checker flags it. In fact, it's a scientific word that describes those little particles of fluff that float in aquatic systems. These little specs floating in the water column have a sinister secret, they harbor antibiotic resistance. Drudge et. al from McMaster University tested four different sites, Hamilton Harbour, impacted by sewer overflow; Sunnyside Beach in Toronto, impacted by wastewater; a rural stream by light agricultural activities; and a remote lake in a natural preserve area in Algonquin Park looking for 54 different known antibiotic resistance genes. As one would expect, the more pollution in the water system, the more antibiotic resistance genes were found. This is yet another reason to keep aquatic environments clean.
Most people think germs on their bodies are a Bad Thing. If they didn't, hand sanitizers, disinfectant soap and bleach would not sell so well. As we learn more about the microbes that inhabit our bodies, we are realizing that the human being is really a superorganism composed of about a trillion human cells and 10 trillion microorganisms. Rarely a microbe will cause illness, but these are transient residents that the body actively removes. Most other microbes that live on us are benign and a significant number of them are critical to our good health.
In the latest issue of Science magazine, Torsten Olszak et. al describes how the microbes we come in contact with as children stimulate natural killer cells (part of the immune system) assisting in their development. Without this contact, the natural killer cells do not develop tolerance and can precipitate immune-related diseases such as irritable bowel syndrome and asthma. This contact must occur during childhood for tolerance to develop.
For over 100 years microbiologists have known, to their great consternation, that in any given environment, at least 90% of all microbes are unculturable. In the last few decades, we have developed molecular tools to see these microbes in the environment and determine their presences and number, but we still cannot bring them into culture. There are all sorts of ideas for why this might be true. Many of these microbes may be slow growing, and the fast growing microbes easily outpace them in laboratory medium. Maybe the media we use is "too rich" for many microbes and we need to create media with more dilute nutrients to capture these shy microbes. Maybe the metabolic demands of these microbes were too difficult to replicate in the laboratory and many of them will not grow. Whatever the reason, as of right now, we are nearly blind when it come to these unculturable microbes.
Topoisomerase I unwinds the DNA during cell replication and is an enzyme that is found in Archaea, Bacteria, and Eukarya. Most every living thing has a homolog. To everyone's surprise, it is possible to create mutations that completely remove the activity of the enzyme, yet have cells capable of growth. These cells are sick, but they can grow. The latest research by Stockum et al. shows that these deletion mutants of topoisomerase I actually have compensating mutations, and in fact loss of topoisomerase I is lethal. This makes much more sense.