A subdivision of microbiology dedicated to the study of bacteria.

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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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218 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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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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31 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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47 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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25 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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111 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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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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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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4k views

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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423 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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152 views

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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59 views

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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69 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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43 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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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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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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165 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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59 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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31 views

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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72 views

Aerobe or facultative anaerobe organism that metabolizes acetate?

I'm assuming bacteria, but will take any suggestions. Organism must survive primarily on the acetate (plus trace elements), but I can give/take electrons, if necessary. Not interested in strict ...
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90 views

Have there been any experiments that duplicate chromosome copies from 23*2 to 23*3 or 23*4?

Deinococcus radiodurans is an amazing bacterium with a fantastic survival rate. It can survive to high doses of radiation, in a complete vacuum and in hydrochloric acid. How does this bacterium ...
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Transportation of bacteria

I would like to take an apparatus containing bacteria to another country (Bolivia) from the U.S.. How do I determine whether I am allowed to do this? The bacteria are: ...
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College Bio Research: Bacteria found on computer keyboards. [closed]

I am a college students brainstorming ideas on different topics that may be appropriate for on-campus research. What I came up with and I would like to give it a try is analyze the different types of ...
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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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Image Processing Suite for bacterial microscopy: Schnitzcells or MicrobeTracker?

I am looking to start doing some work tracking the size and growth of individual bacterial cells in the microscope. In order to analyze the images I need software that can segment the cells, ...
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Are there any gluten-eating bacteria that are readily available?

Is there some yeast or bacterium that will eat gluten? I was hoping for some kind of yeast, but I can't find one. Where could I find one?
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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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Functioning of EDTA

I know that EDTA chelates metal ions. It weakens bacterial cell wall and inactivates the DNases. What is the reason why it can do so ? I guess it can inactivate DNases by altering the ...
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142 views

List of all reported bacteria

I would like to know were to download a table file with all reported bacteria and its corresponding PHYLUM, CLASS, ORDER and FAMILY. Basically, its the same table than this one from GOLD genomes but ...
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49 views

Buy bacteria for experiment?

Where can I buy paracoccus denitrificans? I need it for an experiment. I cannot find online where I can purchase this.
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Does antibacterial soap work chemically?

Normal soap requires scrubbing, does anti-bacterial soap require scrubbing too? Since it (I assume) works chemically, can I produce the same cleansing effect without lathering with soap and using ...
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What are the differences between G+ and G- bacteria?

The distinction between Gram-positive and Gram-negative bacteria is based upon the Gram staining method, that reflects the bacterial wall physical properties. However, this classification involves ...
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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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134 views

Why does beta-2-Thienylalanine inhibit bacterial growth?

I'm trying to obtain a better understanding of the Guthrie Test, which checks whether people have a disease called PKU. The Guthrie test uses bacteria to check for Phenylalanine (the amino acid) in ...
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501 views

How effective are restriction enzymes in protecting bacteria?

Bacteria use restriction enzymes to cut DNA of bacteriophages. Virus mutates really fast. Won't a point mutation in restriction site render the restriction enzymes of the bacteria useless ? So how ...
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Is episome a plasmid or a virus?

A plasmid is a small DNA molecule that is physically separate from, and can replicate independently of, chromosomal DNA within a cell. In general, in eukaryotes, episomes are closed circular DNA ...
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Expression of plasmid genes

Are plasmid genes always expressed? If so, then isn't a bacterium wasting it's resources in expressing genes (like antibiotic resistance) which are not required in "normal" conditions? If not, then ...
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57 views

How do plasmids protect themselves against restriction enzymes?

How do plasmids protect themselves from restriction enzymes released by bacteria (i.e., against bacteriophages)?
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Can viruses protect themselves against restriction enzymes?

Restriction enzymes cut the DNA of bacteriophages. Have bacteriophages evolved any mechanism to protect themselves from it ?
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Do toxin producing strains of E. coli constantly produce toxin or only under certain conditions?

Background E. coli is prevalent everywhere but only some strains produce toxins harmful to humans, such as E. coli O157:H7. Questions 1) Would anyone know if these strains are always producing ...
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Bacterial Conjugation/Horizontal Gene Transfer — how does the plasmid exchange work?

So according to a PPT I'm reading, bacterial conjugation works by the two bacteria joining pili and exchanging plasmids. So how exactly do the plasmids get across the gap? If I understand this ...
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42 views

Do lysogenic viruses only infect bacteria?

In the video sent by my teacher on viruses, the example he used for lysogenic viruses was a bacteriophage infecting a bacteria. When he was describing how the genetic material was incorporated into ...
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27 views

Correlating Ki values of pesticides to bacterial growth

Four pesticides P1 to P4 are reversible inhibitors of an enzyme E that is essential for the growth of a bacterium B. Their Ki values are given in the table below. Each of these four pesticides ...
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Correlating B-lactamase expression to absorbance

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

Why do peas change colour?

I am doing an experiment on preservation of peas. The first notable change to the peas over a period of one week is that they have changed colour from bright green to a dull colour... Why is this ...
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53 views

Why bacteria produce light?

After seeing this video I am curious to know why the free living bacteria produce light. What advantage will they have ? Or is it just an "unintentional" result of one of their pathways ?