6 votes
Accepted

Why are my bacterial smears disappearing?

Bacteriological smears are a one-and-done scenario. Very few of them are intended for repeat use. Basically, all you can expect is that you observe it and then discard the slide. Wiping the oil off ...
bob1's user avatar
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5 votes
Accepted

Can single-Use Gloves carry bacteria on their outer surface?

Short answer - No! These gloves are neither produced nor stored aseptically unless you get ones specifically for surgery. You should always use good aseptic technique when working with viable ...
bob1's user avatar
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4 votes
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Risk with cultures taken from stagnating water?

First off, without knowing the specifics, it is very hard to say, but in general, so long as you are careful and don't ingest (i.e. drink) or breathe in aerosols/droplets of the water, it should be OK....
bob1's user avatar
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4 votes

Is there a reliable method to determine if heat fixation was inadequate before proceeding with further staining steps?

I work with a teaching group who has looked at this, specifically for the aim of making things easy for undergrad labs in under-resourced countries, where gas and/or Bunsens or alcohol burners might ...
bob1's user avatar
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3 votes

Why would it be impossible for gram-positive bacteria to store sulfur as gram-negative sulfur-oxidizing chemolithotrophs can?

I also understand that sulfur cell inclusions are usually elemental sulfur wrapped up in PHA (poly-beta-hydroxy alkanoates) polymer. This is not correct! It is true that most PHA producers generally ...
Philippe VdS's user avatar
3 votes

Can a gene transfer from a plasmid to a bacterial chromosome?

Briefly: yes. It has been known for some decades that plasmids (including those that encode antibiotic resistance) can recombine with the host genome. Indeed, the selective pressure to perform such ...
Maximilian Press's user avatar
2 votes
Accepted

How do microbiologists decide whether two morphotypes on the same plate belong to the same strain?

You have to remember that when a microbiologist looks at a plate, they are looking to observe a particular something, which depends on exactly what they are doing, and they will have some idea of the ...
bob1's user avatar
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2 votes

Storing bacteria in a dry, room temperature long-term storage whilst maintaining viability

Lyophilization, aka freeze-drying, is probably the go-to method of microbial preservation without the need for cold storage. It's how bacterial strains purchased from commercial culture collections ...
MikeyC's user avatar
  • 4,679
2 votes

How do i create sustainable readily available stock cultures to act as Gram stain controls?

Aside from MikeyC's commented suggestion, which I think is a good idea and they should write it up as an answer. In my experience, most species of bacteria you might use as controls for Gram staining ...
bob1's user avatar
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2 votes

Can a non-pure culture be used for reliable rapid phenotypic diagnostic tests?

Isn't the answer in the quote you provided from Manual of Standards for Diagnostic Tests and Vaccines? The results won't be reliable. Having pure cultures by re-streaking the ones you suspect and only ...
bob1's user avatar
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1 vote

Extremophile hunting and identifying unknown microbes

If "identification" is your goal, I would suggest a MinION sequencer and associated equipment for library preparation. These are capable of generating large informative reads for e.g. ...
Maximilian Press's user avatar
1 vote

Can placing a culture plate upright introduce contaminants from the lid?

Are you careful not to have your arms/hands over the lid when you inoculate your plate ? If yes, then I would not worry. But the best way to know if you worked clean enough is to have a control ...
CaroZ's user avatar
  • 332
1 vote
Accepted

Does sunlight interfere with the efficiency of compound light microscope?

I'm not sure that this is exactly biology, more physics, however the answer is sometimes, though this depends on the type of microscope and how the light is impinging on it. This answer assumes a ...
bob1's user avatar
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1 vote

Storing bacteria in a dry, room temperature long-term storage whilst maintaining viability

The answer to this strongly depends on the species of bacterium you are working with. The only ones that I know of that are capable of withstanding any dehydration process are those that form spores. ...
bob1's user avatar
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1 vote

How can one store non-sterile culture media in dissolved form in the refrigerator?

So long as you are careful in making this, so as to not add gross+ contamination (hair, don't put your fingers in it, etc.) and use clean glassware, then a storage at 4 C will inhibit almost all ...
bob1's user avatar
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1 vote

What's the purpose of using more than one culture medium for bacterial isolation?

I am not sure I get your question, Do you want to isolate a sepcific type of bacterium or in general isolate most bacteria from a sample? If you want to isolated a specific bacterium from a samples, ...
efrem's user avatar
  • 267
1 vote
Accepted

Prevention of disease spreading in animal kingdom

Taking the evolution angle, some anti-transmission behavior may be hardwired (not requiring human-level intellect) e.g. an infection usually means symptoms like (high) fever, malaise, fatigue, ...
Agent Smith's user avatar
1 vote

Prevention of disease spreading in animal kingdom

I like the question, and it's an area I've given some thought to. My answer is "yes." Yes, animals have adapted behaviors to avoid getting sick from disease. There's not much motivation for ...
AKeene's user avatar
  • 11
1 vote
Accepted

Concentrating cell concentration after subsampling

So the solution for this can be in two ways: calculate the total number of events (evenst/uL * total volume of sample at time X) and then devide by the initial volume. or perform a correction factor,...
Franco Grosso's user avatar

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