Tea-fueled

Explanatory Productions presents: Listeria Cruise in Infection：Impossible

Sun, 19 May 2013 12:51:00 +0100

Listeria monocytogenes. It was a simple soil-dwelling bacterium, eating decaying plant matter. Until one day, everything changed. Eaten by a cow, and transported into the food chain through dairy and ready-to-eat products, Listeria must fight to survive. It must turn on… its PrfA genes. The basics:

Listeria species are bacteria - Small, one-celled organisms. Bacteria do not have membrane-bound organelles (unlike eukaryotic cells, such as those found in people, animals, yeast etc.) which are like mini organs that the cells uses to compartmentalise its functions.

Listeria monocytogenes (hereafter L. monocytogenes) is a species of Listeria that can live in the soil (as a saprotroph - eating decaying matter) or as an opportunistic pathogen. This means that if it gets a chance to live inside a host, such as a person or animal (usually cows), it will jump at it, like a horny giraffe at another giraffe.
So L. monocytogenes needs to be able to live in both a) a soil environment and b) an intracellular environment.

Needless to say, soil is very different in composition to the inside of a cell. If L. monocytogenes is going to invade a cell, it has to overcome a few challenges. Think of the bacteria as an intrepid, pill-shaped action hero, complete with Batman-style utility belt. It gets itself ingested via that delicious cheese you just snacked on after school. Once it reaches the gut, it activates its automatic transformation into its alter-ego: opportunistic pathogen! Sensing that it is inside another organism, it activates the Positive regulatory factor A (PrfA), which turns on the genes for all of its utility belt tools.

Approaching a cell in the gut lining, Listeria pulls out its first gadget: the Phagocyto-Matic! Using Internalins A and B, the bacterium convinces the cells to let it in through the cell membrane, the bacterial equivalent of flashing psychic paper at the security guards.

This process means the bacterium becomes wrapped in a bubble of membrane, from which it must escape before the cell sends in acidic chemicals to destroy it - sort of like the heroes having to free themselves from the bindings slowly lowering them into the proverbial tank of piranhas. It uses its second gadget, Membrane-Be-Gone (composed of listeriolysins, phospholipases and proteases) to break down the membrane of the phagosome, and escape into the cytosome of the cell, where the ‘treasure’ is.

In this case the ‘treasure’ is Glucose-6-phosphate (G6P), the first intermediate product of glycolysis (part of respiration, the reaction the cell uses to convert sugar and other carbon sources into energy). Conversion of glucose to G6P requires energy input, so by stealing the G6P, the bacterium gets all of the available energy out of the glucose starting substrate without the initial cost. In order to import the G6P, the bacterium needs a special protein transporter: the third gadget, the Yoink-er 3000, hexose phosphate transporter (hpt).

Unfortunately, in true Mission Impossible style, just as the bacterium steals the G6P (and starts to proliferate, which would have made for a very different movie), alarm bells start ringing: the immune system’s Killer T cells are on their way, to destroy the infected host cell and prevent the bacteria from spreading any further. The race is on to escape the cells before the cytotoxic T cells arrive. The bacterium reaches for the last trick in the bag: the reverse grappling hook, actin recruitment protin A (actA). Attaching it to its backside, actA draws in the building blocks of the cell skeleton, normally used to prevent cell collapse, and builds itself a sturdy actin-filament tail. This tail grows and grows, pushing the bacterium towards the outer membrane of the cell and into its neighbour. The membrane closes around Listeria to form the phagosome once again, just as the T-cells reach the first cell and- BOOM.

Listeria has successfully evaded the immune system, and the cycle can begin again in the new cell. Fortunately, Listeriosis, the disease caused by Listeria infection, primarily only affects pregnant women, infants and the immunocompromised. For everybody else, Listeria’s days are numbered.

Watch a video of Listerial actin rockets here.

sherlotter: I am a big Mat Baynton fan so I wrote him a creepy...

Sun, 19 May 2013 09:10:52 +0100

sherlotter:

I am a big Mat Baynton fan so I wrote him a creepy song.

(Mat is best known for Horrible Histories on the BBC, and for his music as Dog Ears, links in the description of the video)

Bump for the morning crowd/Americans/Aussies.

My normally quiet road has a very loud house party on it and I am annoyed because I have to get lots...

Sun, 19 May 2013 01:06:54 +0100

My normally quiet road has a very loud house party on it and I am annoyed because I have to get lots of work done tomorrow and they are keeping me up.

spookyandthethief: I wish there were more people like...

Sat, 18 May 2013 23:36:58 +0100

spookyandthethief:

I wish there were more people like luna

When I grow up, I want to be Luna Lovegood.

I am a big Mat Baynton fan so I wrote him a creepy song. (Mat is...

Sat, 18 May 2013 17:31:00 +0100

I am a big Mat Baynton fan so I wrote him a creepy song.

(Mat is best known for Horrible Histories on the BBC, and for his music as Dog Ears, links in the description of the video)

rosalarian: Angelina Jolie had a double mastectomy, in case you...

Fri, 17 May 2013 17:01:42 +0100

rosalarian:

Angelina Jolie had a double mastectomy, in case you hadn’t heard. How dare she remove those ticking time bombs from her chest, amiright? Like, hasn’t she learned by now that her body is public domain and we all get to vote on what she does with it? Sheesh, how selfish can ya get.

ifellowedsleep: scruplesthecat: Blubberbutt...

Fri, 17 May 2013 16:57:54 +0100

ifellowedsleep:

scruplesthecat:

Blubberbutt Thundermunch.

Accurate. :D

Benedict Calldispatch

It’s funny because my name is actually Benedict.

It’s not far off your actual name though. In tone. :D

ilovecharts: (via juliasegal)

Fri, 17 May 2013 16:56:41 +0100

ilovecharts:

(via juliasegal)

"I’m going to make a store called “Build-a-Bra” where girls can go and make bras that are for them if..."

Thu, 16 May 2013 15:03:03 +0100

“I’m going to make a store called “Build-a-Bra” where girls can go and make bras that are for them if they have different shaped boobs. And really big boobs. And really small boobs. And bras for boys that they can stuff if they want them. And really any kind of boobs. And you’ll choose the size of each cup and then you can choose the color and pattern and shape. And it’ll be really cheap. But lace and diamonds will cost a little extra”

- my 12 year old “niece” Lila on her business idea.

I love that little girl.

(via marrymejasonsegel)

Best idea.

(via shakethecobwebs)

I wanna go

(via godricsgirl)

LACE AND DIAMONDS WILL COST A LITTLE EXTRA!

(via mojoflower)

scottish-love: Dream Street by Evelina Kremsdorf It’s...

Thu, 16 May 2013 10:47:20 +0100

scottish-love:

Dream Street by Evelina Kremsdorf

It’s Victoria street. Supposedly Diagon Alley is based on it.

starrynightcat: DEATH OF RATS Saturday crafternoon with...

Tue, 14 May 2013 11:13:03 +0100

starrynightcat:

DEATH OF RATS

Saturday crafternoon with cloacina ( and mercy-misrule baking in the kitchen) saw two skeletons and a resin-cast rat skull merge into one. A black velvet robe, scythe, rigging up blue LED and battery in the chest cavity and *BAZINGA*.

DANG that coffee table needs re-varnishing…

OH MY GOD

bemusedlybespectacled: if you ever think mythology is boring or serious business or whatever...

Tue, 14 May 2013 11:07:10 +0100

bemusedlybespectacled:

if you ever think mythology is boring or serious business or whatever shit

just remember that cerberus, the hell-hound and guard dog of the underworld, comes from the root indo-european word ḱerberos, which evolved into the greek word kerberos, which got changed to cerberus when it went from greek to latin

ḱerberos means “spotted”

that’s right

hades, lord of the dead, literally fucking named his pet dog spot

djavjr: smileyfacewinkwink: One of my favorite scenes from The...

Tue, 14 May 2013 10:56:39 +0100

djavjr:

smileyfacewinkwink:

One of my favorite scenes from The Great Gatsby (1949)

special effects just ain’t what they used to be

bemusedlybespectacled: kekkes: Someone left this on the table...

Mon, 13 May 2013 18:53:43 +0100

bemusedlybespectacled:

kekkes:

Someone left this on the table I went to go eat at so I took it and true

Every time I see this go around, the first two paragraphs are cut. Fixing that.

marchqueen: “Wakey wakey, boys and girls. Wakey wakey.” IT’S...

Mon, 13 May 2013 09:32:45 +0100

marchqueen:

“Wakey wakey, boys and girls. Wakey wakey.”

IT’S JUST OUR AAAAAAAAAAAAA

AUTOMATONIC

ELECTRONIIIIIIC

HAARRRRMOOOOONICS!

Cry Me a River Song: masterkfox: fullmetal-dipshit: the-nicest-asshole: UK grading system...

Mon, 13 May 2013 08:24:45 +0100

Cry Me a River Song: masterkfox: fullmetal-dipshit: the-nicest-asshole: UK grading system...:

masterkfox:

fullmetal-dipshit:

the-nicest-asshole:

UK grading system
75-100 A+
70-74 A
64-69 A-
60-63 B+
55-59 B
50-54 B-
46-49 C+
43-45 C
38-42 C-
35-37 D
0-34

Time to move to the UK

Dude I would kill for that grading scale

Hah hah oh man I remember I got one…

This is slightly incorrect, at least in my experience.

90-100: A* (High School) / A1 (University)
80-89: A / A2
70-79: B / A3
60-69: C / B
50-59: D / C
40-49: E / pass
30-39: F / marginal fail
0-29: G or U depending on marking body / Clear fail.

And the use of + and - is not common in official marking, but sometimes crops up in classrooms.

(Oh and 80+ grades are not at all uncommon in the sciences)

fannywinkle: “plop.” Menagerie!

Sat, 11 May 2013 07:53:35 +0100

fannywinkle:

“plop.”

Menagerie!

pleonectic: uglly: WHAT IN THE MOTEHRFUCKING HIOLY FUCK ITS...

Fri, 10 May 2013 08:17:12 +0100

pleonectic:

uglly:

WHAT IN THE MOTEHRFUCKING HIOLY FUCK ITS LIK!!!!! MY BABIES IN 1 PICTURE?!?!?!?!!

Axolotls!!!!!

Axolotls!!!!

Photo

Fri, 10 May 2013 08:13:55 +0100

molly23: billcorbett: “He’s charming. He serenades me. With...

Fri, 10 May 2013 07:30:40 +0100

molly23:

billcorbett:

“He’s charming. He serenades me. With a banjo!”

“He’s a CRUSTACEAN.”

“So I always wear strange green outfits. We all have our things, our weird things.”

“[SIGH]”

vintagegal:

“The Serenade” by B. Wennerberg, 1914

That’s really not that impressive because banjos are tuned to a chord anyway, so his left claw is basically just acting as a guitar slide and his right claw is a giant plectrum. Anything with no fingers and an exoskeleton could still passably play the banjo.

NOT IMPRESSED, LOBSTER.

I also worry that he’s straight up going to puncture the drum head if he holds his claw like that, and then she’s going to have to replace it because he probably can’t grip a damn screwdriver.

I HAVE PROBLEMS, WITH THIS PICTURE AND ALSO JUST OTHERWISE.