Influenza viruses are a great threat to humans and have very well proven their pandemic nature such as the H1N1 pandemic in 2009. They contain the protein haemagglutinin (HA) which determines the host range by identifying specific receptors such as sialic acid linked to galactose by α2,6-linkages in humans. Recent studies at UW-Madison and University of Tokyo by Yoshihiro Kawaoka have identified a reassortant H5 HA/H1N1 virus that can be transferred through droplet transmission in a ferret model and is capable of identifying Siaα2,6Gal linkages.
A recent Penn State experiment studied the effects of weak immune systems on the virulence and aggressiveness of a malaria parasite in mice. The study involved disabling a key immune molecule, CD4 receptors, with an antibody and then infecting these mice and a control group with an uncompromised immune system with the malaria parasite Plasmodium chabaudi. It lasted 21 weeks and each week, the parasite was taken from one mice and transferred to another previously uninfected mouse. They froze the samples biweekly to analyze aggressiveness and virulence.
The ability of bacteria to develop resistance to antibiotics has posed as an ongoing obstacle for the medical community. Antibiotic resistance becomes evolutionarily favorable when the resistant microbes are able to thrive within a community. This in turn creates a pressure to maintain these mutated microbes and weed out the susceptible ones. Since mutated organisms are less fit, when resistance is no longer needed the original strain can thrive once again.
Overuse of certain antibiotics is to blame for this dilemma, however antibiotics are often the only known treatment for certain illnesses. Recently, scientists at Harvard University’s Wyss Institute for Biologically Inspired Engineering have discovered a new way of engineering antibiotics to trick the already resistant bacteria. Silver has been very useful for certain medical tools such as catheters and tracheal tubes due to the low infection rate however until recently no one understood why this was the case. Ruben Morones-Ramirez, Ph.D. investigated the mechanism in which silver affects bacteria and discovered that silver has many properties that alter the bacteria. Firstly, silver creates more reactive oxygen species in the bacteria which in turn damages both enzymes and DNA. It also affects the membrane by making it leakier and therefore weaker.
Obesity is associated with increased risks of certain types of cancers, such as colorectal and liver cancer. The mechanism behind this relationship in humans is still unknown, but recent research has shown that gut microbiota may play a role. Scientists at the Cancer Institute of the Japanese Foundation for Cancer Research in Tokyo studied the relationship between gut microbes and the development of liver cancer using lean and obese mice. By exposing the mice to a cancer-causing chemical shortly after birth, all of the obese mice and a few of the lean mice developed cancer. The cancerous tumors in the obese mice contained a very high level of deoxycholic acid (DCA), which is known to damage DNA and cause inflammation of the liver. DCA is a byproduct of the break down of bile acids by certain gut microbes. The next question was what led to the increased levels of DCA. The scientists found that the obese mice have a different mix of bacteria in their guts, including gram-positive bacterial strains that are less existent in lean mice. They proved that this mix of bacteria was associated with increased DCA levels. An antibiotic targeting the gram-positive bacteria led to decreased DCA levels and reductions in cancer incidence.
Therefore, the mechanism is as follows. Obesity causes gut microbiology changes. Gut bugs that are gram-positive bacteria strains leads to elevated levels of DCA in the body. The more DCA present, the greater the risk for developing liver cancer. If further research proves that a similar mechanism is seen in humans, then this information can be used to screen for liver cancer and to decrease ones risk of developing cancer.
Zombies seem to be all the rage recently in the entertainment industry. Obviously, Hollywood generally avoids keeping things “scientific” for entertainment purposes, but could it be possible to be controlled by another biological organism? Well, a Czech Scientist named Jaroslav Flegr sure thinks so. Flegr came to this idea when he noticed that he would do dangerous acts, like crossing the street, without thinking twice about it. He made the connection when he read about how a flatworm invades the nervous system of an ant. Usually, when the temperature drops, ants burrow underground, but the infected ant actually climbs to the top of a blade of grass, and locks onto it as hard as possible. It does this in an effort to be swallowed up by a sheep eating grass, so that it may complete its life cycle. Flegr believes something similar is happening in humans when they are infected by T. gondii, a microbe that is found in cat feces.
It turns out that vitamin C is a switch for gene activation inside mouse stem cells. A recent study that was conducted by UC San Francisco researchers made it possible to help guide normal development in mice, humans and animals, improving results of in vitro fertilization and growing healthy stem cells in the near future. What happens is that vitamin C assists a specific group of enzymes called “Tet” which are activated during the early stages of fertilization and development. This collaboration acts upon removing specific molecules called methylene groups. These groups when added to DNA at certain points through out the genetic material stop particular genes from being activated.
<font face="Times New Roman, serif" style="color:rgb(0,0,0);font-size:medium;">A recent study, conducted by Professor Seth Bordenstein of Vanderbilt University, proposed that two species of jewel wasp, <font face="Times New Roman, serif" style="color:rgb(0,0,0);font-size:medium;">Nasonia giraulti</font><font face="Times New Roman, serif" style="color:rgb(0,0,0);font-size:medium;"> and </font><font face="Times New Roman, serif" style="color:rgb(0,0,0);font-size:medium;">Nasonia Vitripennis</font><font face="Times New Roman, serif" style="color:rgb(0,0,0);font-size:medium;">, remain separate species largely because of microbe interference, not lethal incompatibility in DNA, as many biologists believed.</font></font>
Growing interest in nuclear power is often hindered by the question of what to do with the radioactive byproducts. One solution is to bury them. In Mol, Belgium, at the HADES research center, scientists have discovered communities of microbes living in the clay surrounding structures that house nuclear waste. Some species of microorganisms are known to have detrimental effects on the materials used for these structures. Researchers have delved hundreds of meters underground in search of what kinds of microbial communities are present, and what relationship they might have with the poisonous compounds we've introduced to them
Normally when one thinks of microbes, they don’t imagine them being able to be mechanically cut as one cuts an onion. Microbes are extremely small and we don’t have blades fine enough to get the job done. However, researchers at Brown University have shown that the cell membrane of human cells can be cut by graphene microsheets. Graphene is a relatively new nanomaterial that is a two dimensional layer of repeating carbon and is made by exfoliating it off of chucks of graphite using special technique. Graphene has many exciting potential uses as it has remarkable electronic, mechanical, and photonic properties despite its thin nature. While it hasn’t yet been a large contributor commercially, the potential for the future is there. However, before it can be sold to the general public and hit the markets, it must be confirmed that it is safe. Being relatively new, not much is known about how graphene might affect the body. Due to its small size, it is possible for graphene to get into the body in a variety of ways, including inhalation. Graphene may also in intentionally injected into the body to utilize its biomedical capabilities.
Vaccines have been made ever since Edward Jenner created one for smallpox in the late 18th century. The 19th century saw a handful of vaccines created while the 20th witnessed a boom in creation. Today the process of making a vaccine in the United States is highly regulated by the FDA as well as the CDC. However, creating a vaccine is not a straightforward process. There are multiple ways in which a virus or bacteria and be used to create a vaccine that will protect a person for years to come.
Scientists at Stanford University have created a useable vaccine for Type 1 Diabetes mellitus. This disease affects many people around the globe by decreasing the amount of insulin produced by the pancreas, causing high blood sugar in patients. Type 2 diabetes (aka "adult onset" diabetes) is caused by the body's inability to use insulin properly, whereas type 1 diabetes ("juvenile" diabetes) results from the body's inability to produce insulin. The lack in insulin in type 1 patients has been attributed to the destruction of insulin-producing beta cells in the pancreas by the body's own immune system
Cholera is an infectious disease caused by the bacterium Vibrio cholera and is responsible for thousands of deaths every year. A study conducted in Bangladesh has provided researchers evidence that the human body has developed ways to combat this disease. Researchers have discovered that, due to the high prevalence of cholera, the genomes of individuals in Bangladesh have been altered to fight off cholera. These findings also exemplify how human evolution is still occurring in this day-and-age.
Cases of cholera have been discovered all throughout the world, but the most prevalent area of cholera infections is the Ganges River of India and Bangladesh. In fact, cholera has been prevalent in this area for more than a thousand years. The microbe is responsible for causing diarrhea and promoting severe dehydration, which can cause death within a few hours if not treated.
Researchers at the University of Veterinary Medicine, Vienna have developed an efficient method in determining if a bacterium can cause diseases or if it lacks the potential.
The scientists have been studying the different strains of Staphylococcus aureus and how they behave within the host. S. aureus that lack capsules are less recognized by the host's immune system compared to those that have capsules and are more susceptible to recognition. These two different strains are vital to preventing pathogens from causing chronic infections within patients. The ability to distinguish the two strains is essential in preventing serious health problems for patients.
Recently, it has been discovered that mycobacteria, have the “best of both worlds” when it comes to reproduction. They use a type of DNA transfer, called Distributive Conjugal Transfer, to swap genes with other mycobacteria. After the genome is thoroughly mixed, the bacteria is able to replicate asexually. Because these organisms are able to obtain a “genetic blend” of DNA from parent bacteria (a type of quasi-sexual reproduction), and also replicate individually, it seems that they are reaping the benefits from both types of reproduction, with none of the disadvantages.
Sexual reproduction is costly for organisms. Only half of the population can produce offspring; the other half must fight it out to ensure their genes are passed on to the next generation. The benefit of this replication is the genetic variance; the mixing of two genomes allows the offspring to be better suited for survival. The new combinations could be more favorable to environmental conditions, and also may help separate advantageous mutations from harmful ones.
Streptomyces are gram-positive, filamentous bacteria that are often found in ground soils. They are prolific produces of antibiotics. These microbes survive by secreting toxic antibiotics in an effort to kill surrounding, competing microbes. Different strains of Streptomyces produce different secondary metabolites (antibiotics and other secreted chemicals). The presence of secondary metabolites can either inhibit or promote the growth of a cell. With this in mind, Kalin Vetsigian and Roy Kishony (Harvard Medical School) examined interactions between 64 different Streptomyces strains in order to catalog their positive and negative interactions.
A new study conducted by El-Halfawy and Valvano has demonstrated how resistance to antibiotics can be communicated to other less resistant bacteria through secreted chemicals. They investigated the mechanism of resistance to a bactericide, polymyxin-B (PmB), in resistant strains of Burkholderia cenocepacia, a species that causes severe infections in patients with cystic fibrosis.
Malaria is a parasitic disease spread by mosquitoes that causes an estimated 1 million deaths per year. Four different types of Plasmodium parasites can cause malaria and in many regions of the world these parasites have developed resistance to a variety of the medicines used to treat malaria. It is believed that the development of a vaccine will be the most effective way to decrease the amount of deaths caused by this disease. In the past, vaccine development for malaria focused on inducing antibodies that are able to recognize antigens found on the surface of the parasites. However, this type of vaccine has so far been unsuccessful due to the numerous polymorphisms found in the proteins that make up the surface of the parasites, These polymorphisms enable the parasites to evade the host's immune system. In the past ten years, different methods have been used to research the effects of infecting rodents with low-density blood-stage infections of the Plasmodium parasites to induce immunity.
Scientists at the Wyss Institute for Biologically Inspired Engineering at Harvard University have gained new insight into the dangers associated with long-term antibiotic usage. The scientists, led by Jim Collins, Ph.D., have discovered the cause behind hazardous side effects resulting from long-term usage of antibiotic drugs and have proposed two solutions to prevent and reduce these negative effects.
Doctors have been prescribing antibiotics under the general assumption that the drugs harm only bacterial and not human cells. Contrary to this belief, adverse effects such as tendonitis, hearing loss, diarrhea, and kidney dysfunction have all been reported with long-term use of antibiotics. The research team at the Wyss Institute found that these side effects occur as a result of human cells suffering oxidative stress, causing damage to DNA, proteins, and lipids. Collins proposed that the oxidative stress arose from production of chemically reactive oxygen molecules, those oxygen molecules being responsible for the damage occurring in the cells.
Knowledge about microbes has proven to be useful for gaining a better understanding of the environment. As an example, phytoplankton – a photosynthetic marine microorganism – was discovered to be a source of half the Earth’s supply of oxygen, thereby providing insight to our relationship with the ocean.
However, researchers currently have an understanding about only a tiny fraction out of millions of existing microbial species. The problem is, most marine microbes cannot be cultivated with the same conditions used for laboratory bacteria. A recent study published in an edition of the Proceedings of the National Academy of Sciences, explains why this is so.
Antibiotic resistance in both pathogenic and nonpathogenic bacteria is becoming an urgent topic in human health. According to the Center for Disease Control and Prevention, antibiotic resistance is developing in more and more bacteria. Resistance has been the cause of over 90,000 deaths nationwide, typically from patients with preexisting autoimmune diseases. Studies have been done to determine why more bacteria are acquiring resistance genes and the origin of these genes.
Typhoid fever is a predominantly gastric bacterial disease that is found worldwide and is caused by the bacterium Salmonella entrerica serovar Typhi (S. Typhi). Typhoid is one of the most well documented diseases in history having ravaged populations as old as the Athenians of ancient Greece and as new as the citizens of Chicago less than a century ago. Modern sanitation and hygiene practices have all but eradicated the disease in developed nations but developing nations are still heavily impacted with over 200,000 deaths annually. S. Typhi is very closely related to the more well-known Salmonella strains that cause a usually non-fatal, if uncomfortable, case of gastroenteritis. Up until very recently it was not known why this strain, that is almost identical genetically, causes a systemic and life-threatening disease while its cousins did not.
Surprisingly, the human body consists of more bacterial cells than human cells. An important region where bacteria reside is the intestinal tract. The bacterial community present plays an important role not only in food absorption, but also in the body’s immune response. The bacterial community is dynamic and adapts as its environment, the human body, changes. As the title suggests, researchers hypothesized that HIV infection would have a significant impact the intestinal bacterial community and that this change in part causes the chronic inflammation found in many HIV patients.
A unique three-tiered symbiotic relationship is now being studied in order to better understand how organisms transfer and share genes in mutualistic interactions. Surprisingly, this gene transfer is not analogous to how mitochondria and chloroplasts have evolved with their host genome.
In early life, one is exposed to thousands upon thousands of microorganisms. The most affected organs are naturally the gastrointestinal tract and the lungs, as they are constantly exposed to the outside world. How one is affected via microbial exposure during this early stage of life could have an effect on them throughout their life. This article discusses the benefits of these early exposures to microorganisms in the way of preventing diseases later on.
Prion-like protein accumulation in brain cells helps explain Alzheimer’s and other neurodegenerative diseases
When looking at the damaged nerve cells of an Alzheimer’s patient under a microscope, one observes clumps of proteins that seem out of place. Researchers have discovered these protein masses behave much like prions – malformed proteins normally found in healthy neurons. These contorted proteins in turn cause like proteins to misfold and bind to one another, resulting in a chain reaction or cascade that destroys entire regions of the brain. Prions are most commonly associated with the contagious neurodegenerative mad cow disease, however all evidence suggests Alzheimer’s and Parkinson’s lack the infectious agent of classic prion diseases. Regardless, these recent findings provide scientists with a “signpost” for neurodegenerative diseases that may point toward eventual treatment options for the millions of patients suffering around the world.