4
votes
2answers
56 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 ...
5
votes
1answer
145 views

Calculation of the bacterial growth rate from a spectrophotomer growth curve

Typically the microbial growth in liquid cultures is monitored by turbidity. Data is obtained with a spectrophotometer to measure optical density at 600nm. The slope of the bacterial kinetic curve in ...
3
votes
1answer
41 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 ...
-1
votes
1answer
244 views

I don't wash my hands and never get sick. Any theories? [closed]

I have only been sick a few times in my life(I'm 21 and probably 3-4 times) and even when I am sick I don't feel that bad and I am over it within a day or two. My family has always given me slack for ...
0
votes
0answers
49 views

Replication of DNA in E. coli: what are DARS and RIDA?

I understand what is DnaA, its role in replication and the fact that it's only active when binding ATP. I don't understand what are DARS and RIDA and how they control the amount of DnaA-ATP:DnaA-ADP
0
votes
1answer
36 views

What is the maximum amount of different bacteria in the drinking water in Europe?

I am looking for a statistical amounts which are allowed. Some students say it is 0 for all bacteria, which I think is false. I found this USA source. I found there Total Coliforms (including fecal ...
1
vote
1answer
56 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 ?
1
vote
1answer
154 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 ...
3
votes
1answer
70 views

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 ...
0
votes
1answer
21 views

How to get conservation of vaccine candidates between hundreds of bacterial strains?

We have identified vaccine candidates via an ex-vivo RNA-seq approach. Next step would be to perform conservation of these candidates (about 20) between multiple bacterial strains (about 200). I would ...
1
vote
3answers
93 views

Assay for Beta-galactosidase activity in single cell microscopy

I'd like to be able to measure the activity of $\beta$-galactosidase in living cells with simple optical (maybe fluorescence) microscopy. Ideally I'd like to do a minimum of genetic engineering, and ...
1
vote
0answers
24 views

Improving throughput of CFU plating?

In a separate question I've described my general experimental setup where I need to measure the number of live cells in a growing bacterial culture in a fairly rapid and high-throughput manner. In ...
6
votes
1answer
246 views

Alternatives to CFU plating for measuring number of viable cells?

I am hoping to measure growth rates of a bacterial culture in several growth conditions. I am concerned that these growth conditions may cause cell death, which would lead to a decreased ...
2
votes
0answers
171 views

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, ...
4
votes
2answers
654 views

Why do different bacteria have different shapes?

Why do different bacteria have different shapes? Is it only related to their function?
0
votes
2answers
237 views

What are artifacts in microbiology?

What kind of objects can be qualified as artifacts? How do we distinguish such objects?
2
votes
1answer
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 ...
3
votes
1answer
250 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 ...
1
vote
0answers
60 views

What are some readily available, easy to test, bacteria?

I want to do a science fair experiment about how bacteria interact with 5-carbon vs. 6-carbon sugars, and I want a bacteria that is easy to test and is readily available. Any ideas?
2
votes
1answer
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 ...
1
vote
1answer
78 views

Is iodised salt harmful to the lactofermentation process?

I was discussing sauerkraut recipes with someone on IRC a minute ago, and they warned me not to use iodised salt in the process. My first (and so far, the only successful) batch is one I made with ...
6
votes
1answer
644 views

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? ...
1
vote
1answer
35 views

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 ...
1
vote
1answer
888 views

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 ...
5
votes
1answer
149 views

Is there a practical upper limit to amount of nucleotides or genes in a transformed plasmid?

I'm currently working on a synthetic biology project which involves working with lots of different parts. I would ultimately like to integrate these genes by transforming a single plasmid. I've heard ...
7
votes
1answer
349 views

How is the exogenous DNA protected from degradation during bacterial transformation?

During transformation, a bacterium can take up DNA from its environment. A small fraction of bacterial species are known to be naturally competent, meaning that they can engage in this sort of ...
5
votes
1answer
1k views

Why are pili more common in Gram negative bacteria than in Gram positive?

Although pili have been observed in some species of Gram positive bacteria, the preliminary research that I have done indicates that pili are significantly more common in Gram negative bacteria. Is ...
7
votes
2answers
823 views

Bacterial cell lysis - what solution to use?

I am trying to determine how quickly detergents act on bacterial cells (cell lysis). I would like to compare some detergents at difference concentrations for bacteriolytic activity. I don’t care about ...
5
votes
2answers
408 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, ...
5
votes
1answer
117 views

Mutation-immunity in Luria-Delbruck experiment

If experiments like those of Luria and Delbruck on E. coli and T1 phage are the main source of our confidence in the mutation-immunity model, is it then highly unlikely that there are other types of ...
4
votes
2answers
404 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 ...
5
votes
1answer
316 views

Aren't antibiotic resistant probiotics dangerous?

Multidrug resistant probiotics are often recommended by doctors in various cases. But since bacteriae can easily exchange genes by conjugation or other means they could promote the drug resistance of ...
10
votes
2answers
3k views

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 ...
5
votes
1answer
1k views

What is the distinction between F' plasmid and R plasmid?

Is there a difference between an F' plasmid that has taken up a chromosomal gene that conveys antibiotic resistance, and an R plasmid? Is a bacterium containing an R plasmid and yet lacking an F+ ...
21
votes
2answers
8k views

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 ...
10
votes
1answer
131 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 ...
10
votes
2answers
141 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 ...
14
votes
2answers
210 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 ...