AP Biology class blog for discussing current research in Biology

Tag: #toxin

Has anthrax, a microbe globally known not to be messed with, become a medicine?

Researchers from the Harvard Medical School have recently shown a potential medical breakthrough with an animal pain study. They have discovered how the bacteria Bacillus Anthracis can silence the feeling of pain in a mouse experiment while not destroying the nerve cell to do it.

Bacillus anthracis Gram


Anthrax has been viewed as a deadly bacteria ever since its discovery, causing skin lesions, fatal lung infections, and many other problems in both humans and animals. Anthrax secretes a couple of toxins after it infects the animal and these toxins can be deadly. The specific anthrax toxin used in the pain experiment has the ability to alter the signaling between pain-sensing neurons and relieve pain in the mice. As they continued their research they combined the anthrax toxin with other molecular cargo and discovered that this treatment can be used to create pinpoint precision pain treatments. Opiods are used now to treat pain in patients but they can be very dangerous and addictive. The toxin would act on pain receptors to possibly be a more effective and more safe painkiller than opioids.  ““There’s still a great clinical need for developing non-opioid pain therapies that are not addictive but that are effective in silencing pain,” said study first author Nicole Yang, HMS research fellow in immunology in the Chiu Lab. “Our experiments show that one strategy, at least experimentally, could be to specifically target pain neurons using this bacterial toxin””(Science Daily). This wouldn’t be the first time a toxin has been used to treat pain since Botox is used today to treat some pain and is approved by the FDA to treat migraines.

This all started in a lab, with researchers trying to figure out how many pain-sensing neurons there were compared to other neurons in the body. They discovered that pain neurons had anthrax receptors, just like the receptors that we worked on in class. The anthrax receptor uses endocytosis to bring the anthrax toxin into the cell. Research led to the dorsal root ganglia, a link of neurocensors in the spine. They relay pain signals to the spinal cord that then combine with two proteins that are created by anthrax itself. Experiments revealed that this occurs when one of the bacterial proteins, protective antigen (PA), binds to the nerve cell receptors and forms a pore that serves as a gateway for two bacterial proteins, edema factor (EF) and lethal factor (LF), to be brought into the nerve cell. The research further demonstrated PA and EF together, known together as edema toxin, alter the signaling inside nerve cells in an attempt to silence pain.

When the toxin was injected into the spine of mice, it produced incredible pain-blocking effects. It prevented the animals from feeling high temperature and mechanical stimulations. Throughout all this, the animals heart rate, body temperature, and full motor control was not affected, indicating that the use of the anthrax toxins may be safe to use in humans in clinical studies. This lab breakthrough shows how much we still have to discover about a bacteria that has been on the earth for thousands of years. Although many bacteria and viruses haunt us now, as we progress and have more discoveries like this, who knows what the world will look like when I’m 50!

Does Exposure to Toxins In the Environment Affect One’s Offspring’s Immune System?

A study has recently surfaced stating that maternal exposure to industrial pollution may harm the immune system of one’s offspring and that this impairment is then passed from generation to generation, resulting in weak body defenses against viruses.

Paige Lawrence, Ph.D., with the University of Rochester Medical Center’s Department of Environmental Medicine, led the study and conducted research in mice, which have similar immune system functions as humans. Previously, studies have shown that exposure to toxins in the environment can have effects on the respiratory, reproductive, and nervous system function among generations; however, Lawrence’s research is the first study to declare that the immune system is also impacted.

“The old adage ‘you are what you eat’ is a touchstone for many aspects of human health,” said Lawrence. “But in terms of the body’s ability to fights off infections, this study suggests that, to a certain extent, you may also be what your great-grandmother ate.”

“When you are infected or receive a flu vaccine, the immune system ramps up production of specific kinds of white blood cells in response,” said Lawrence. “The larger the response, the larger the army of white blood cells, enhancing the ability of the body to successfully fight off an infection. Having a smaller size army — which we see across multiple generations of mice in this study — means that you’re at risk for not fighting the infection as effectively.”

In the study, researchers exposed pregnant mice to environmentally relevant levels of a chemical called dioxin, which is a common by-product of industrial production and wast incineration, and is also found in some consumer products. These chemicals eventually are consumed by humans as a result of them getting into the food system, mainly found in animal-based food products.

The scientists found the production and function of the mice’s white blood cells was impaired after being infected with the influenza A virus. Researchers observed the immune response in the offspring of the mice whose mothers were exposed to dioxin. Additionally, the immune response was also found in the following generations, as fas as the great-grandchildren (or great- grandmice). It was also found that this immune response was greater in female mice.  This discovery now allows researchers to have more information and evidence to be able to more accurately create a claim about this theory.

As a result of the study, researchers were able to state that the exposure to dioxin alters the transcription of genetic instructions. According to the researchers, the environmental exposure to pollutants does not trigger a genetic mutation. Instead, ones cellular machinery is changed and the immune response is passed down generation to generation. This discovery explains information that was originally unexplainable. It is obviously difficult to just avoid how much toxins you are exposed to in the environment, but it is definitely interesting to see the extent of the immune responses in subsequent generations. We can only hope that this new information, and further discoveries, help people adjust what they release into this world that results in these harmful toxins humans are exposed to, and their offsprings.




Lead Leads to Neurotoxitity

Have you ever heard of using bottled water to shower? Sounds ridiculous right, but the people of Flint, Michigan need to do this to save their lives. The city of Flint switched their water supply from Lake Huron to the Flint River in April 2014. The river was later discovered to be contaminated. Since the changeover, scientists have linked the high lead levels in children’s blood to the contaminated water. This is a serious problem.

Lead is a highly toxic substance that permanently affects humans’ brains by killing nerve cells. Not only does lead harm kids’ brain processes, it also may cause various future mental diseases, such as Alzheimer’s disease and Schizophrenia. Throughout U.S. history, people have been exposed to lead poisoning through basic everyday mediums, such as paint, water (from lead-contaminated water pipes), and dust. Children who eat paint chips or lick their fingers after coming in contact with products that have a lead component are poisoning themselves. The lead enters into the bloodstream and travels throughout the body, stealthily making itself at home, poisoning the body.

So how does lead poisoning work? Basically, lead disguises itself as zinc. Zinc is needed to anchor proteins that switch genes on and off. When zinc is replaced with lead, the switches cannot function properly, eventually leading to mental diseases.

Lead Poisoning

Scientists have been researching the possibility that lead is transferable in DNA to offspring. This could be devastating to a population of a town like Flint, Michigan, where the mothers who have lead poisoning could pass this on to their babies. The worst part is that there is no cure for lead poisoning.

Because of the devastating effects of lead in bloodstream, governments have debated the topic of legalizing contaminated water as a bioweapon, using lead as the contaminant. Governments in the past have used poisoned water as an assassination method, proving the effectiveness of this strategy.

Preventing lead exposure and poisoning is critical for children’s health and for future generations.


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For more info on the biowarfare, click here.

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