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Mari
02 October 2015 @ 09:04 pm

Credit to allstarzs.

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Current Mood: energeticenergetic
 
 
Mari
The road to Botulism starts with a simple Clostridium botulinum. This bacteria has not been infected by the proper bacteriophage yet, so it has yet to become the tougher and virulent strain people associate with this particular bacteria. As with all other organisms in this world,  this C. botulinum suffers an attack by a virus (of course, the ones that specifically target bacteria are called bacteriophages). What is fortunate for the bacteria is this 'phage will not undergo a lytic cycle of multiplication, which would have essentially lysed the bacteria with all the virions being created inside it like some bad horror movie (aka that one Cloverfield scene). Instead this temperate bacteriophage goes inactive and it's viral DNA becomes one with the C. botulinum to make it virulent and able to release toxin into the environment. This process of lysogenic conversion is one of a handful of methods of gene exchange that is important to the evolution and changes to the genetic makeup of bacteria, as they can not increase diversity via reproduction. It should also be noted that as a member of the genus Clostridium, C. botulinum has the natural ability to produce endospores, a nifty trick some bacteria (some pathogenic, some not) can do to withstand a harsh environment (like extreme heat when boiling the liquid or food it might be in) and can only be killed by burning or an autoclave.

The next step would be for the bacteria (an obligate anaerobe) to contaminate an environment with plenty of nutrients but low amounts of oxygen, like a can of food.  Swollen cans are an obvious sign for an anaerobe infestation as no other microorganism could handle the low oxygen and anaerobes still give off some gas byproducts in either fermentation or anaerobic respiration.

Once the contaminated food is consumed, the toxins the virulent bacteria produce works to inhibit the release of acetylcholine, which is necessary for muscles to respond to nerve impulses to contract. Death from Botulism is due to respiratory failure when a patient loses their ability to contract the diaphragm. As one of the most deadly toxins known to humans, it takes less than .0001 milligrams to kill a healthy adult.



As a side note, Botulinum toxin is also used in medical procedures, some of which happen to be cosmetic.
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Current Mood: anxiousanxious
 
 
Mari
29 November 2010 @ 05:10 am
Microbiology, Genetics, and Ecology happened to coincide in giving me the largest workload I have seen expected within a few days in my entire college career and I NEARLY forgot to do this blog. Coincidentally, because of the largest chunk of said work is Micro, I thought to combine it with the main theme of what the highlight of my Thanksgiving should have been - Food.

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Current Mood: restlessrestless
 
 
Mari
14 November 2010 @ 10:28 pm
This entry will attempt to explain how lead poisoning works, but first, an introduction to the circulatory system from the vlogbrothers!

their enthusiasm is both admirable and mildly unsettling, or is it just me?Collapse )
 
 
Current Mood: lazylazy
 
 
Mari
"To reduce the severity of his seizures, Joe had the bridge between his left and right cerebral hemisphers (the corpus callosum) severed. As a result, his left and right brains no longer communicate through that pathway. Here's what happens as a result:"

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Current Mood: relaxedrelaxed
 
 
 
Mari
24 October 2010 @ 11:44 pm
The rest of Dr. Najeeb's Intro to Immunology lecture can be found here. I particularly enjoy that he draws during the lecture to get the subject across rather that just showing a diagram. It allows for a progression of the material that is much easier to follow.
 
 
Current Mood: nerdynerdy
 
 
Mari
26 September 2010 @ 10:09 pm
Who doesn't love Dopamine?

Dopamine is the neurotransmitter essential to motivation, learning, and the brain's reward circuitry - in other words, enjoyable activities will cause a rush of dopamine into brain areas already primed for reward/pleasure. 

Dopamine - it encourages sweeping.
Hopefully not to the point that a sweeping habit becomes a serious problem.

It is also happens to be essential for what we consider regular movement that might get us to pleasurable activities - even if that just means getting to and sitting down in the office chair in front of your PC. Deep within the brain is the basal nuclei, which control movement in an inhibitory fashion. They will inhibit muscle tone, turn off useless/unwanted movements, and coordinate slow contractions like ones associated with posture and support. The best example of what happens when this is not functioning normally is Parkinson's Disease. Gradually the useless and unwanted movements of the body are manifested in tremors, and rigidity of the muscles, often those associated with posture, make it hard to initiate and follow through with new movements (like getting in and out of a chair as quickly as one is normally used to).

TL;DR - Dopamine makes fun activities fun and voluntary movement into/out of desk chairs less tasking.
 
 
Current Mood: sicksick
 
 
Mari
07 September 2010 @ 03:35 pm

(Not so) Suprisingly, DNA on its own will not completely determine an individual. While this is sometimes used as a cheap "evil twin" plot device, it holds true because of a molecular body known as the epigenome. It governs expressivity of the underlying coding and is itself affected by environmental factors such as stress, drug exposure, and diet. While not to the extreme of effecting morality, this potentially explains why one identical twin might develop a condition like diabetes or asthma while the other does not.  What is most interesting about the field of Epigenetics is that environmental factors can effect subsequent generations long before they were ever concieved, which is what researchers in Sweden looked to examine in their northernmost county of Norbotten. 

During the timeline that was being examined, Norbotten had:
  1. Extreme isolation from the rest of Sweden - meaning less genetic variations in the population.
  2. Agricultural Independence - Locals eating locally grown food, meaning no sudden surge in food quantity thanks to outside influence.
  3. Distinct time periods of extreme famine  and abundance - making it easier to point out which individuals had experienced what type of consequent eating habits through life.

Adults who had experienced even one winters worth of overeating  as children were shown to produce offspring with a lower lifespan than their famine-enduring counterparts. Depending on the constraints on other variations possible, the difference in longevity ranged from 6 to a whopping 32 years! And it's not just the overeating of today that can cause the problems of future generations. Epigeneticists have been looking into the smoking and drinking habits of adults when they were in their youth, too. For example, one study saw an increase in a son's BMI depending on their father's smoking habit before and during his teen years.

TL;DR - The cheeseburger and cigarette of today can plummet the life expectancy of your kids tomorrow.

Thanks Epigenetics!

Source: Time Magazine
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