Questions tagged [microbiology]

Microbiology is the study of extremely small organisms. This includes organisms like bacteria, fungi, protozoa, and viruses.

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What is the effect of non-vaccinated people on vaccinated people?

Many times have I heard that anti-vaccine people are dangerous even to the vaccinated population. Is that true? If so, how can it be? People say that germs will attack them, and soon they would ...
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99 votes
7 answers
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Do beneficial viruses exist? If so, what examples are there?

Typically, people call viruses some kind of organic compounds that cannot reproduce autonomously and which lower the fitness of their hosts. Even the word "virus" means "venom" in Latin. But from the ...
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39 votes
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Can bacteria be killed by purely physical trauma?

In a question over on Skeptics Stack Exchange, I half-jokingly listed "blunt force trauma" as a means by which a bacterium could be killed. That makes me wonder if it really is only a joke ...
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5 answers
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Is there an advantage to antibacterial soap?

There are plenty of different hand soaps out there, as well as hand sanitizers. Is there an advantage to soaps that claim that they're antibacterial vs soaps that just say soap? In particular I'm ...
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Can a bacterium infect another bacterium?

I researched about it by searching on Google and reading some bacteriological articles, but I did not get any answer. I also asked some of my teachers, and they were also a bit confused. Some said ...
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29 votes
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If a human takes antibiotics are all bacteria in the body killed?

From my basic understanding, antibiotics kill living things, bacteria for example. Do the antibiotics consumed by a human-being distinguish between what they kill? Or do they just kill every bacteria ...
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25 votes
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Hot water and bacteria

I know that it is common to say, "use hot water when washing your hands" or when you've got a cut, "wash your hands with warm water," etc. I was wondering, why is this the case? Since bacteria grow in ...
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24 votes
2 answers
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How does the microbial environment in your gut initiate?

Clearly, a zygote does not harbor any microbes. As it develops, and the alimentary canal tissue is differentiated, I logically assume that there is still no microbial activity in the fetus's gut. I'm ...
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23 votes
3 answers
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Are single-celled organisms capable of learning?

I've read that the amoeba is capable of learning. Since these protists have no nervous system, it's safe to assume that even highly simplified learning mechanisms of the Aplysia are miles off in the ...
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Why is 70% ethanol preferred for aseptic techniques?

Are other concentrations (say 80%) less effective,or is this just for convenient manufacturing? Is the concentration chosen only because it is less volatile than 100 percent ethanol and hence safer?
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21 votes
1 answer
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Is there any convincing evidence for the existence of nanobacteria?

The existence of nanometer scale microorganisms has been proposed and used explain several phenomena including morphological structures in a martian meteorite (ALH 84001) and implication in the ...
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Can Biologists identify all viruses?

I went to the doctor today with my girlfriend, and the doctor said that she had a virus but doesn't know which one and she should let the infection heal with some rest. The fact that the doctor didn'...
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4 answers
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How to understand influenza strain designations?

What do the strain designations for flu mean? For example avian flu is classified as H5N1, what do the letters H, ...
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Why don't we have vaccination against all diseases caused by microbes?

People can be vaccinated against certain diseases. Principle of vaccination is to use live attenuated load or inactivated. My question is - why we dont have vaccination against all diseases which are ...
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19 votes
4 answers
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Are red blood cells prokaryotic?

After searching "do antibiotics impact the immune system" I found out that antibiotics target prokaryotic cells. It all made a lot of sense thinking about all those yogurt recommendations you get ...
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18 votes
4 answers
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Why don't antiseptic agents kill 100% germs?

I've seen innumerable antiseptic, mouthwash, handwash advertisements that claim to be able to eliminate as much as 99.9% of all germs over a surface...but why not the remaining 0.1% (i.e- why can't ...
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Are viruses self-propelled?

So obviously, viruses are nonliving. But when my teacher was teaching viruses in the video (we're doing "flip" learning this semester), the way he described it, it seemed like the viruses responded to ...
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18 votes
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Why is there now only one Salmonella species?

Once upon a time, I chanced upon an old microbiology book that detailed the rather colorful world of enterobacteria. Salmonella in particular stood out, as it seemed there were a lot of species: typhi ...
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18 votes
2 answers
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Are there single-celled organisms that have evolved from multi-cellular ones?

I'm reading this paper about transmissible cancer cells in clams (Metzger et al. 2015) and I was wondering if there are any single-cellular organisms that are around today that are suspected as having ...
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3 answers
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Why does an autoclave need to pressurize steam?

I've looked this up on other sites and they say that an autoclave needs high pressure in order to raise the boiling point of water so that you can achieve steam of a higher temperature. If you look ...
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17 votes
2 answers
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Why does mouldy food make you sick?

Bread gets mouldy pretty quickly. My parents (both of whom are nurses) throw out a loaf of bread after a spot of mould is seen (because "if you can see one spot, it means the whole thing is covered in ...
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Do probiotics survive digestion?

Pretty much this. I've been wondering if any of the yogourt and other "health" foods containing living probiotic cultures survive digestion to populate our intestines? If so, is there peer-reviewed ...
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17 votes
1 answer
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Antibacterial soap impacts on septic system?

What impacts do antibacterial soaps have on septic systems? I know that septic systems rely heavily on bacteria (especially regarding the breakdown of wastes by bacteria), so it seems as though ...
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17 votes
1 answer
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How can Valonia ventricosa cells get so big?

Valonia ventricosa are single-celled algae that range between one and few centimetres. In rare cases, they can reach sizes exceeding 5cm. They range from grass-green to dark green, and some are even a ...
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1 answer
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Why are there 2 copies of RNA in the HIV virion?

There are two copies of the RNA in the HIV virion. These are retroviruses. So, they can make cDNA from even just one copy using reverse transcriptase. What is the use of the other? Are both ...
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For how long would a flu-contaminated parcel be an effective disease vector?

A parcel has been delivered and contaminated by a person who has the flu. For how long would the parcel be an effective disease vector?
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15 votes
1 answer
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How to obtain bacteria samples at home?

As the original question went from hold to closed, I thought I would write up a more appropriate question. How should one go about getting bacterial samples to look at under a microscope at home? ...
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15 votes
1 answer
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Can anyone ID this microorganism?

I found this microorganism in a wet moss sample taken from my backyard in Richmond, Virginia (USA). I took some pictures of it at 40x, 100x, and 250x. I'm not entirely sure what it is, but I think it'...
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15 votes
2 answers
324 views

Relationship between our microbiome and personalized nutrition

Recently, it has been asked whether there are 'metabolic types' between humans that can benefit from a sort of personalized nutrition. One answer suggested that one discerning factor could be the ...
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15 votes
2 answers
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What is the meaning of multicellularity?

I can't understand what multicellularity is. Wikipedia states that any organism having many cells is multicellular. By this definition bacteria can also be multicellular. For example, cyanobacteria ...
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14 votes
2 answers
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What kinds of bacteria live in water bottles?

I've always heard not to re-use disposable plastic water bottles. According to this Huffington Post article, the reason is because: everyday wear and tear from repeated washings and reuse can ...
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14 votes
1 answer
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How heavy are all foreign microorganisms in and on the human body?

I define "foreign microorganism" as a microorganism which is not produced by the human body (not antibodies or leukocytes) including bacteria, viruses, fungi, biofilm aggregates or small lifeforms ...
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14 votes
3 answers
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How are antibiotic resistant bacterial infections treated?

For example, how are infections of antibiotic resistant strains of MRSA, Streptococcus, or Gonorrhea treated?
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14 votes
1 answer
194 views

Are there animal models for Clostridium difficile that better replicate human infection than hamsters?

So I'm looking for some information on the infectious dose necessary to colonize a human with Clostridium difficile. There's no human challenge studies, and since it's not a foodborne pathogen, little ...
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13 votes
3 answers
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How do baby animals that primarily subsist on cellulose get their initial gut flora?

In the case of mammals like giraffes and koalas, is that bacteria common on the plants they eat so when a baby starts to try to stick something besides its mother's milk in its mouth, it can't digest ...
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13 votes
4 answers
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Can viruses be toxic?

Bacteria can produce toxins like endotoxins and exotoxins. In diseases like cholera or tetanus they can harm infected people due to these toxins. Now, although viruses are much smaller and are ...
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12 votes
1 answer
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Do all bacterial cells have a double membrane?

I’m reading that gram positive and negative bacteria have an inner plasma membrane surrounding the cytoplasm, then a periplasmic space, then an outer membrane. How does this compare to my general ...
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12 votes
2 answers
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Why is the microbial ecosystem of the gut so susceptible to disruption by pathogens?

From all accounts, it seems as if the Escherichia, Enterobacter, etc. that live and thrive in the human gut are pretty well entrenched. I know that these microbial populations are often analyzed as ...
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12 votes
2 answers
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Is there an equivalent to "Fields Virology" for Bacteria?

I've gotten a staggering amount of use out of my copy of Fields Virology as a general reference for "getting me up to speed" on whatever pathogen I'm currently looking at. I don't know of a similar ...
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12 votes
2 answers
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Antibacterial hand soaps (and related products); what are they good for?

From Wikipedia: Household use of antibacterials in soaps and other products, although not clearly contributing to resistance, is also discouraged (as not being effective at infection control). ...
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12 votes
2 answers
334 views

Is there a favoured mathematical model of bacterial growth?

One of the most regularly measured phenotypes in bacterial synthetic biology is growth. Anyone who does wet lab microbiology or synthetic biology will have performed a growth curve measurement. ...
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12 votes
1 answer
395 views

Which is the reference 16S rRNA?

Recently, I've stumbled upon a fact, which hasn't bothered me for many years. The fact is that all universal 16S primers are written as "[FR][0-9]+" (in regex notation), that is they have a position ...
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11 votes
2 answers
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What is the advantage of using starter cultures for growing bacteria?

Many DNA isolation and protein expression protocols contain instructions to use a starter culture of E. coli that is then used to inoculate the main culture. What are the advantages of using starter ...
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11 votes
3 answers
11k views

How much weight/volume do microbes occupy within the human body?

Microorganisms constitute the bulk of all the biomass on Earth. I weighed myself yesterday, and wondered how much less I would weigh if I were completely free of bacteria and microbes, inside and out. ...
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11 votes
2 answers
866 views

Can bacteria release free DNA into their environment?

Natural transformation AKA natural competence involves the uptake of DNA into a competent bacterium (for horizontal gene transfer or as a food source). My question is about where this extracellular ...
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11 votes
3 answers
240 views

Non-harmful bacterial invasion of cells

There are bacteria that can enter body cells as parasites. Could it be that some of these are benign, such that the guest will not kill the host cell it lives in (especially in human)?
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11 votes
1 answer
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Are these Gram stain substitutions acceptable?

In the context of a Gram stain on a blood smear: Are the following acceptable substitutions and/or what differences could arise by substituting them? Using methylene blue instead of crystal violet ...
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11 votes
0 answers
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What is this fuzzy, black fungus that grew on my plates in the 4⁰C room? [closed]

I often find the fungus below growing on my (ostensibly) sterile plates in the 4⁰C room. Presumably it takes a few days to reach this size. The colony looks puffy and dimpled in the middle, like a ...
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10 votes
4 answers
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Does a microwave oven disinfect food?

Imagine I am preparing food -- just about to put it into a microwave oven -- and some of it falls on the floor. Assuming it got some bacteria or other organisms (viruses?) on it, will the microwave ...
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10 votes
2 answers
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Difference between Peptone, Peptide and Proteose

In my school textbook, it is given that Pepsin converts proteins to peptones, proteose and peptides. What is the difference between the three products? On googling the terms, the definition was ...
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