A subdivision of microbiology dedicated to the study of bacteria.

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How does heat shock transformation work?

What exactly happens when competent cells like DH5ɑ are heatshocked with DNA present? How does the DNA get inside the cells? Specifically, why are all the steps necessary? What if you heatshock right ...
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107 views

Is 1 g/l living biomass for a Biogas fermenter plausible?

A usual number for a healthy biogas fermenter is $10^9 - 10^{10}/mL$ Bacteria, 10-15% of which would be methanogenic archae. Exceptionally healthy fermenters have more total bacteria and up 25% ...
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490 views

Sparking during electroporation of plasmid DNA into bacterial cells

During electroporation of bacterial cells (I work with Mycobacterium tuberculosis, but I think this applies to E. coli as well), sometimes I get sparking. I've read this is due to salts present, ...
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187 views

What is the mechanism of oxygen uptake in E. coli?

How does E. coli uptake oxygen? Most of the literature I found is concerned with response to oxygen level supplied in the medium, as opposed to how much is actually transported inside. Can they shut ...
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191 views

Gas from bacteria that's not methane

Is gas produced by bacteria always mainly methane? Or, are there bacteria out there that produce some biogas composed mainly of hydrogen, natural gas, propane, butane?
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Blood consumption

Is consumption of blood more "dangerous" compared to meat? There was a news-article about unnatural chemicals found in the blood of mothers. This reminded me about a question I have pondered upon ...
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50 views

Correlating beta-lactamase expression to absorbance

When penicillin-resistant bacteria are grown in liquid culture media, β-lactamase is secreted into the medium. The supernatant of such a medium can be assayed for β-lactamase activity. ...
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445 views

Does making yogurt from non-pasteurized milk work against possible disease bacteria?

In the past, when there was no pasteurization, could making yogurt from milk lower the chance of getting infected by bovine tuberculosis (or other diseases from infected milk)? For example, would ...
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56 views

How often does bacterial transformation happen?

I have been reading: M. Dröge, A. Pühler, W. Selbitschka, "Horizontal gene transfer among bacteria in terrestrial and aquatic habitats as assessed by microcosm and field studies", Biol. Fertil. ...
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52 views

Is there any way the food industry can benefit from biofilms?

I realize all of the disadvantages, but I am wondering if the food industry can actually benefit from the formation of biofilms.
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330 views

How do I measure bacterial growth in agar dishes (either by cell mass or by cell count)?

I am doing an experiment in which I am growing S. mutans in agar dishes, and I am not sure how I would measure the growth of the S. mutans. I am also not sure if I would do this by measuring cell mass ...
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86 views

Why do plasmids replicate on their own?

I know how plasmids can replicate independently of the main genome and know that they confer various properties to the bacteria and are useful in conjugation. My question is - what is the advantage ...
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122 views

Does conjugation support gene selection?

I have already posted this on chat but haven't got any response. A recent question on group selection stimulated me to ask this here. QUESTIONS: Why should bacteria conjugate? If we consider that a ...
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67 views

How can I save bacillus strains on filter paper without an -80 degree freezer?

I want to save my bacillus strains but I don't have access to a -80 degree freezer. What are possible alternatives?
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539 views

What are gram negative and positive bacteria?

I've just finished a course of double antibiotics for Helicobacter pylori in my stomach. I looked up H. pylori and found that it was a gram-negative bacterium. I looked up gram-negative and didn't ...
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151 views

What is a bacterial biofilm?

Bacteria produce something called a biofilm. I have found a few definitions; some say it is a complex of live and dead bacteria and others say it is a layer on cell wall. What is it made of? What ...
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41 views

What does the gene name “lexA” stand for?

It is an important gene expressed in E. coli that represses the SOS response and also the expression of lambda lytic phase genes. UV light and damage to DNA is responsible for its breakdown and hence ...
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How long can C. Tetani survive in soil?

Clostridium tetani (C. tetani) is a bacterium commonly found in soil and is excreted in the faeces of many animals (both mammals and birds) and serves, by means of the exotoxin, tetanospasmin, causes ...
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Restriction endonucleases are found in?

Quoting from : Scientific American July 1975 The Manipulation of genes by Stanley Cohen : Restriction endonucleases (and modification methylases) are widespread in microorganisms; genes for ...
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When might an inhibitor of bacterial transformation be useful?

I am part of a project elucidating some structures that are required for bacterial transformation. We have the opportunity to screen inhibitors of the system to stop it from functioning. I am not a ...
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112 views

How does sucrose protect bacterial cells in lysozyme solutions?

I have a microbiology question. When we put bacterial cells in sucrose solution with concentration higher than 0.5M we observe plasmolysis - the cytoplasmic membrane detaches from the cell wall due ...
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50 views

What is the film that covers the tongue?

What is the film that covers the tongue in the mornings, even after brushing the teeth and tongue the night before and why does it have color variations? Do the different colors mean anything?
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31 views

Functioning of BCG vaccine

I read (from Nature Volume507, S4–S7 (06 March 2014) : For reasons that are poorly understood, BCG protects only infants; it is ineffective in older children and adults. Its efficacy also ...
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Could the growth rates of Vibrio vulnificus be affected by an oil spill?

I live on the Gulf Coast, and Vibrio vulnificus has recently made the news due to an increase in the number of reported infections. Naturally, it has people around here worried. I live in an area that ...
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138 views

What is the length of anaerobic biodigestion stages?

I have built an experimental portable batch biodigester to process organic garbage. A 50L drum filled half with garbage, half with water and with some cow dung added for inoculation, is connected from ...
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Do sulfate reducing bacteria help during the formation of the mineral dolomite in low temperature environments?

Do sulfate reducing bacteria help during the formation of the mineral dolomite in low temperature environments? Wikipedia says The actual role of bacteria in the low-temperature formation of ...
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114 views

Cheapest Way to Measure Germ Density

I would like to measure the surface density of Staphylococcus bacteria and Rhinoviruses (only those two, to be specific) within my home. What's the cheapest way? The textbook procedure is to: rub ...
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Is there a specific word for bacterial death?

What do you call it when a bacterium dies? Cellular death is apoptosis, necrosis, and bacterial is ...? I don't simply want to write in a paper that it - well dies!
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How quickly is antibiotic resistance lost?

I would imagine the bacterial genome is highly conserved and limited in its space, but maybe I am wrong. If you were to take a strain of antibiotic resistant bacteria and kept them isolated, but fed ...
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Why isn't Bubonic Plague as virulent as it once was?

Although I am admittedly not anywhere near an expert on any topic, I still have a hard time understanding how Black Death and Bubonic plague are one in the same. Since plague still exists, with news ...
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Why are bacteria and archaea in different domains?

As I understand it, the main difference between the Bacteria and the Eucaryota domains are that eukaryotes have a nucleus and bacteria don't. I understand that bacteria and archaebacteria have enough ...
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505 views

Why does ampicillin in solution turn yellow?

I have a universal tube with 10 mg mL-1 ampicillin. When I got it, it was supposed to be sterile. It was opened for approximately 20 minutes for an experiment and has since been standing around sealed ...
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Can antibiotic resistant bacteria compete with normal one in an antibiotic free environment?

The question is based on an intuition that antibiotic resistance can't come along. This mutation will probably make bacteria less tenacious. Is there any research how AR bacteria compete with normal ...
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How do a viruses or bacteria survive outside the body long enough to spread?

Say I cough on my table, then someone else touches it and picks up something I've got... how is it that these things can live outside the body, how long can they manage it, and how long is generally ...
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Aside from cockroaches and other insects, which species (of all kinds) are 'immune' to ionizing radiation?

I have just been reading this excellent question and answer about cockroaches ability to withstand ionizing radiation. My question is an extension of that question: aside from insects, which other ...
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75 views

Whence fecal E. coli (et al.) if swallowing it is dangerous?

I don't know much about medicine, and I know even less about microbiology, but I understand that there are organisms in the lower gastrointestinal tract (and in feces) of a human, like Escherichia ...
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34 views

Do bacteria with multiple flagella move faster than bacteria with a single flagella?

Do bacteria with multiple flagella move faster than bacteria with a single flagella? Assuming the flagella are at the same length.
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64 views

Production of processed Insulin in bacteria

Genetically-engineered bacteria are used to produce insulin in industry, but as far as I know, the bacteria can produce only proinsulin. Why is that? What happens in the human body in order to make ...
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37 views

Are added yogurt cultures harmful to the gut?

I have read somewhere that the live culture added to yogurt acting as "healthy" gut bacteria are actually synthetic and harmful. Any truth to this? If so, what are some alternatives to getting good ...
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49 views

Quorum Sensing in Vibrio cholerae

This is a figure summarising the quorum sensing mechanism in Vibrio cholerae. In this video by Bonnie Bassler, she explains how quorum sensing can be targeted to control infections. At 15:09 she ...
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Why restriction enzymes cut (usually) at palindromic sequences?

Restriction enzymes usually cut only at palindromic sequences. Is there any specific reason for that ? Is there any advantage for bacteria if it cuts up virus at this type of sequences ?
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Medium for Pseudomonas?

What is a good minimal medium for Pseudomonas bacteria? Do I need different media for different Pseudomonas species?
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Speciation and Phylogeny of Lactobacillus

The lactobacillus, also called Döderlein's bacillus is a genus of facultative aerobic bacteria. There are several species such as Lactobacillus acidophillus and Lactobacillus reuteri. I have several ...
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57 views

Why is Thermus aquaticus and Taq Pol stable?

What is the molecular basis of the stability of the bacterium Thermus aquaticus and the enzyme Taq Pol it produces ? I have tried googling this but did not get a good answer.
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247 views

Mesosome - does it exist?

This wikipedia page says that mesosomes are artifacts produced by chemical fixing techniques. Most of my textbooks still show a mesosome and describes it as having functions like - respiration, ...
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194 views

How much natural genetic variation is there between bacteria of the same species?

There are lots of questions about how and why there is genetic variation between organisms of the same species, but I haven't been able to find a numerical value for the expected amount of genetic ...
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63 views

Extract bacteria from compost?

I'm working on a project where I need to find certain cellulolytic bacteria. I was looking at this list : ...
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Which strains of C. diphteria are causing Diphteria toxin?

I got this question: Diphteria toxin is produced only by those strains of C. diphtheria that have which of the following characteristics? Encapsulated glucose fermenters lysogenic for b-prophage ...
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1answer
56 views

Will an 11W UVC lamp kill bacteria?

If I shone a UVC lamp (11W) on something (say for example a plastic phone case) for an hour, would that kill off a noticeable amount of bacteria? That is, if I were to go over the case with a cotton ...
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35 views

What makes certain obligate anaerobes viable in fermentation starter cultures?

If Propionibacterium are obligate anaerobes (to wit, poisoned by oxygen), what makes 'Dairy' or classical propionibacteria (e.g. P. shermanii, P. jensenii, P. acidicpropionici, et al) viable in ...