Questions tagged [microbiology]

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

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103
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4answers
10k views

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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6answers
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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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5answers
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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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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 ...
25
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3answers
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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 ...
22
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2answers
462 views

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 ...
21
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2answers
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Why we don't have vaccination against all diseases which are 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 ...
21
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2answers
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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 ...
21
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1answer
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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 ...
20
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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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4answers
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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, ...
20
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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?
19
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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 ...
18
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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 ...
18
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2answers
351 views

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 ...
18
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2answers
770 views

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 ...
17
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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 ...
17
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3answers
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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 ...
17
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1answer
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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 ...
17
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1answer
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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 ...
16
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2answers
6k views

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?
15
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1answer
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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? ...
15
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2answers
307 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 ...
14
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1answer
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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 ...
14
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1answer
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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 ...
13
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2answers
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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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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 ...
12
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1answer
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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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3answers
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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 ...
12
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2answers
307 views

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 ...
12
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2answers
249 views

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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How are antibiotic resistant bacterial infections treated?

For example, how are infections of antibiotic resistant strains of MRSA, Streptococcus, or Gonorrhea treated?
12
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2answers
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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). ...
12
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1answer
326 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 ...
11
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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 ...
11
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2answers
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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 ...
11
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2answers
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Does freezing microorganisms such as probiotics kill them?

Does freezing microorganisms such as probiotics kill them? If not, what is the process that allows them to "come back to life" after the temperatures are increased? As an example, lets say you ...
11
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3answers
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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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780 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 ...
11
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3answers
231 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)?
11
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1answer
490 views

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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0answers
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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 ...
10
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2answers
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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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3answers
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Inoculation vs. vaccination

Is there any actual difference between inoculation and vaccination or are these terms interchangeable? In case the difference exists, would it be correct to say that inoculation is purposefully ...
10
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1answer
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Can Naegleria fowleri enter through wounds into the bloodstream?

All the sources I've read said that Naegleria fowleri enters the brain through the nose. But lets say that someone had cuts on their arm or leg and they are swimming in water that is conducive to ...
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What is this microscopic image from Peter Gabriel's New Blood album cover?

This image appears on the cover of Peter Gabriel's album New Blood. It appears to be a photograph of some microscopic biological cell. But it doesn't look like a blood cell to me. What kind of ...
9
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4answers
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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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3answers
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Why is triclosan not considered an antibiotic?

Triclosan is a chemical often referred to as a "biocide" instead of an "antibiotic". However, its mode of action seems to suggest that it is an antibiotic. Triclosan binds to bacterial enoyl-acyl ...
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2answers
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Is working with (nitrile) gloves around a bunsen burner safe?

Recently I have started in a new microbiology lab, and with a new lab come new habits. When I was working with my bacterial (liquid) culture next to the flame (Bunsen burner) wearing nitrile gloves, ...
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Does rainwater contain many fewer micro-organisms than river water?

From watching many documentaries on micro-organisms, I can tell water typically contains quite a lot of them. But what about rainwater? (before it hits the ground). I know nothing about any micro-...