09:22 – Here’s the working cover that we’ll use for marketing materials and so on.
Mark Paglietti, the cover designer, commented, “Far be it from me to suggest filling in some white space, but there is a huge hole in the middle that could use some additional items… But, it works fine for our immediate purposes.” I was trying to come up with something to fill in that white space. I thought maybe a hand-drawn and labeled DNA molecule would be a decent background when it finally hit me. Duh.
My actual microscope workstation is a large desk that makes an “L” with my main office desk. Sitting at the back of that microscope desk is a wooden shelf organizer that’s full of bottles of stains and other reagents, spare slides and coverslips, a microtome, and other microscope accessories. So I just shot a quick image of that to send to Mark and Brian to ask what they think. If they agree, I’ll set up that organizer as a background for the microscope and other stuff in the current image, positioned to leave white space for the “Includes” column down the left side.
11:09 – Someone asked me what’s in the tubes stoppered with cotton balls. They’re broth culturing tubes. Ordinarily, they’d contain some sort of nutrient broth, such as LB or diluted beef broth with sucrose or glucose added. In this case, they contain a special culturing broth made up of tap water to which I added five drops of red food coloring and one drop of green. The advantage is that it doesn’t need to be autoclaved; the disadvantage is that nothing actually grows in it.
Barbara went out on the front porch for a few minutes after dinner last night. While we were out there, Melissa and her husband drove by and waved. She was about due to have her baby, so I walked down to see if she’d had it yet. She did, on October 5th, a little girl to go with her pair of very active little boys. I was quite proud of myself because I went through a mental checklist of things women always want to know about new babies. Name? Scarlet Gray. Check. Sex? Female. Check. Dimensions? 6’8″ and 18 pounds. Check. (When I told Barbara, she said it was highly likely that I’d confused the dimensions, which she thought were probably 6 lb. 8 oz. and 18 inches.)
While I was standing talking with Melissa, she asked what I was up to with the biology book. (She’s a biologist.) I told her I was working on a group of lab sessions on bacteria culturing, and the conversation went something like this:
Her: Oh, what species are you culturing?
Me: I have no idea.
Her: Well, where did you buy them?
Me: I didn’t buy them. I just used environmental bacteria.
Her: (horrified) So you have no idea what you’re growing?
Me: No, other than from the color and morphology of the colonies. I have one that’s a beautiful golden yellow color. (implying that I might have a colony of S. aureus, a dangerous human pathogen.)
Her: Well, you better dispose of those carefully.
Me: Sure, but before I do that I’m going to use them in some other lab sessions. I want to use natural (forced) selection to develop a multidrug-resistant strain by repeated culturing of the survivors in a broth with antibiotics added.
Her: (really horrified) Which antibiotics?
Me: Well, obviously, amoxicillin, tetracycline, ciprofloxacin, sulfamethoxazole, metronidazole, and all the other mainstream antibiotics. I also have some vancomycin, linezolid, and daptomycin, so I’m wondering if I can develop a strain that’s immune to all known antibiotics, including the last-ditch ones.
I finally told her that I was practicing my straight face, and that, no, I wasn’t going to breed multidrug-resistant pathogens. I actually expected her to hit me (women do that a lot), but she just seemed relieved.
And, speaking of saying outrageous things with a straight face, Mary Chervenak told me that if there was anything at all she could do to help while Barbara was recovering just to say the word. I was going to tell Mary with a straight face that I really needed her to clean our house. Fortunately, I have a finely-honed survival instinct. I feared Mary’s Fist of Death even when she was on the other side of the planet during her run around the world, so I’m certainly not going to risk the FoD when I’m standing face-to-face with her.
Actually, that’s not fair to Mary. If she really thought I was serious, I have no doubt that she’d come over here and clean house for us. Wearing a respirator, because she’s deathly allergic to dogs.
8 Comments and discussion on "Friday, 14 October 2011"
“Mark Paglietti, the cover designer, commented, “Far be it from me to suggest filling in some white space, but there is a huge hole in the middle that could use some additional items… But, it works fine for our immediate purposes.” I was trying to come up with something to fill in that white space.”
How about just leaving it blank? There is a limit to how much you can aesthetically fit in to a design. Lots of people don’t know that and produced really cluttered work.
“Me: No, other than from the color and morphology of the colonies. I have one that’s a beautiful golden yellow color. (implying that I might have a colony of S. aureus, a dangerous human pathogen.)”
It’s not really dangerous. Well, it is if you’re immunocompromised. There’s a roughly 25% chance that any of us have S. aureus in our throats or nostrils.
Sure, we all have lots of pathogens on and in our bodies, and our normal immune systems can deal with them. But there’s a big difference between the relatively small numbers normally present and a culture of S. aureus. It’s like the difference between swimming in a river with one crocodile every hundred kilometers versus a river with one croc every ten meters. In the former case, you’ll probably be fine. In the latter, not so much.
If any agencies that rate/approve such books has a sticker on it, the sticker can go in the blank space. Depending on who’s giving you the thumbs up, it can go bigger or smaller. Well, not microscopically small [G]. But otherwise, anything to detract from the open space will do the job. Otherwise, I actually quite like the cover.
Why are cultures stoppered with cotton instead of caps? Because it doesn’t matter and cotton is easy, or because it allows slow pressure equalization (no exploding?) I guess the latter, but that’s just a guess.
A couple reasons. First, when you autoclave the tube, a sealed cap produces pressure in the tube, which can burst it. (You can usually just leave the cap in place but not screwed down to avoid this.) Second, while the culture is growing, the cotton plug lets pressure escape (for example, from carbon dioxide produced during fermentation of sugars by yeasts).
Here’s a biology question:
What pH does food need to be to be safely stored at room temperature. Lots of hot sauces and condiments contain vinegar and are safely kept on the table for weeks and months at a time (so long as they’re capped to prevent mold). Also, if it contains sugar does the pH need to get more acidic as the sugar content increases?
Depends on the food and the organism. Most lifeforms are evolved for near-neutral (pH 7) conditions, but there are acidophiles among bacteria, arachaea, and even some eukaryotes. These thrive at pH levels of 2.0 and lower, which is more acid than vinegar. pH is only one aspect of food preservation in the absence of sterilization. Another major one is osmosis. That’s why salted meat stays good; the very high concentration of salt basically sucks the water out of microorganisms the same way salt sucks moisture out of slugs. But it needn’t be salt. Any high concentration of a soluble material produces osmotic pressure that draws water out of many microorganisms, both dehydrating them and sometimes actually rupturing the membranes. Sugar also works, which is why honey is sterile (other than spores, most famously Clostridium botulinum, which are resistant to osmotic pressure).
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