Have questions about Ebola? Experts at University of Michigan School of Public Health put together a series of videos about how the virus works, why the current outbreak is so bad and how much we should be concerned. You can find the rest of them here.
Ruptured bacteria cell.
I’ve seen a couple pictures like this and they’re always so neat to me. :)
A plasmid is a small circle of DNA that in nature often contains genes for special functions, such as those that allow the bacterium to become antibiotic resistant, express a sex pilus, or create toxins to kill off competing bacteria. They’re also often used as a way to get new genes into bacteria during genetic engineering.
Modern electroconvulsive therapy (ECT) used for major depressive disorder and severe mania associated with bipolar type I disorder. Typically reserved for individuals who feel medications aren’t effective, the ECT provides an electrical stimulus to induce a generalized seizure. While the exact mechanism is unknown, the electrical activity somehow “resets” the depression or mania and provides relief. When done in a safe environment the major side effects are confusion and transient retrograde amnesia (you might forget bits and pieces of the months prior to the procedure).
Very interesting! ECT was originally developed by two Italian physicians in 1938 and replaced more dangerous methods of “shock,” such as insulin shock therapy (where a patient would be given high doses of insulin, causing them to fall into a coma and occasionally emerge with fewer symptoms) and metrazol therapy (where seizures were induced via the stimulant metrazol.) Prior to the advent of antipsychotics in the 1950s, ECT was used pretty indiscriminately in state hospitals, and was originally administered without muscle relaxants (succinylcholine would not undergo clinical trials until the early 50s) which along with horrific media portrayals contributed to its bad rap.
In what’s being hailed as a scientific first, researchers in Scotland have created a fully functional organ from scratch inside the body of a living animal. The feat—the creation of a working thymus gland from “reprogrammed” embryonic …
Wow! The thymus is a very important organ—a type of immune cell called a T cell migrates from the bone marrow to the thymus to mature. T cells are part of the body’s immune response to specific invaders. Their functions include killing virus-infected cells, secreting chemicals to rally other immune cells, and keeping the immune response from going out of control. While the thymus itself shrinks with age and is nearly gone after puberty, what remains of it continues to produce T cells later in life to replenish the ones that die off.
An interesting note about embryonic stem cells: they’re taken from a stage in development called the blastocyst. This is the stage right before three layers of cells form—the ectoderm, mesoderm and endoderm—which give rise to the different tissue types. The point where these layers form, which occurs at around fourteen days into development, is the boundary after which the embryo can no longer separate and form twins. For the purposes of stem cell research, it’s thus usually the point where the embryo is considered a discrete organism, and harvesting stem cells is done before the fourteen day mark.
Let’s talk about Ebola!
The Ebola virus, which was first isolated during a 1976 epidemic in Zaire and Sudan, is an irregularly-shaped, threadlike virus with its genetic information in the form of RNA. It’s thought that its natural reservoir is fruit bats, who can carry Ebola without getting any symptoms, and we know that monkeys can also get infected with Ebola and pass it on to humans. How the monkeys get it isn’t known—they might munch on fruit that’s been partially eaten by the bats—and aside from a few cases where people have butchered monkeys for food, the origin of most Ebola outbreaks tends to be murky.
After a 2 to 21 day incubation period in the body, the symptoms of an Ebola infection tend to come on suddenly, starting with a fever and headache and leading to vomiting, diarrhea, and a nasty rash. In advanced cases, bleeding from multiple orifices occurs, followed by multi-organ dysfunction and death. The fatality rate can be from around 50-90%, with the Zaire strain being the most fatal. The strain currently going around is 97% identical to the Zaire strain.
There’s no specific treatment for Ebola and no vaccine for it exists. Patients are only contagious after the symptoms start and then begin shedding the virus in some of their bodily fluids, so preventative measures—like those full-body suits health care workers wear—aim to keep people out of contact with those fluids and stuff they might’ve gotten on. The virus doesn’t seem to survive in saliva very well and doesn’t show up in urine, which is good news for anyone worried about foodborne or waterborne transmission. Most exposures are probably through blood, and the virus might also appear in semen and breastmilk.
If you care about public health, you’ve got to care about mental health. As a group, psychiatric disorders cause more social and financial cost worldwide than any other group of disorders—and they’re closely related to such major causes of disability and death as heart attacks, strokes, diabetes, and Alzheimer’s disease.
Check out this educational drama throwback, created by the International Health Board in 1920 on hookworm, and which one reviewer called “the best and only film of its kind on hookworm disease.”
Oh my gosh, this is so cool! The life cycle of the parasite is shown correctly (hookworm does indeed penetrate the skin, go from the heart to the lungs, then get swallowed to end up in the small intestine) and the disease is still diagnosed through examination of a stool sample. Though no longer a problem in the US due to advances in sanitation, it’s still an issue in poorer parts of the world, such as sub-Saharan Africa and southeast Asia.
An interesting note about hookworms: they and some related worms are currently being studied as a treatment for conditions like allergies and Crohn’s disease. The idea behind this is that humans coexisted with parasites for so much of history that without them, the immune system tends to malfunction. Clinical trials have been going for a decade or so, with some promising results.
Yesterday I got back from a trip to Yellowstone where I had the opportunity to take photos of some really interesting microorganisms! The beautiful coloration of the Morning Glory pool here is due to billions of thermophilic (heat-loving) organisms. The first of these were discovered in 1965, living happily in the park at temperatures around 82 to 88 degrees C, and about a year afterwards a particularly important one was isolated—Thermus aquaticus. Two decades later, T. aquaticus would serve as the source of Taq polymerase, the heat-resistant enzyme that made it possible to rapidly copy DNA through PCR, revolutionizing molecular biology.
How do microorganisms survive at temperatures like that? Their main challenge is keeping their structures from coming apart, so many have cell membranes and proteins with higher levels of molecular bonding than usual. Their DNA often has more guanine and cytosine than adenine and thymine—this is because G and C stick together with three hydrogen bonds, while A and T only use two.
These organisms also may account for the possibility of damage by having multiple chromosome copies on hand and cleaning up mRNA (which is ‘read’ by cellular machinery to make proteins) quickly, before it has the chance to start getting messed up. If temperatures get really bad—above what an organism likes—many produce heat shock proteins. These work as molecular chaperones, making sure that other proteins fold correctly and don’t assume forms that aren’t functional.
It’s worth noting that these organisms are thought to be similar to early forms of life, especially because many deal with additional challenges that were found in ancient environments, such as high pressures, high salt content and lack of oxygen. In this way, they can serve as a neat window to the past.
Photo is mine, information is from here.