Questions tagged [bacteriology]

A subdivision of microbiology dedicated to the study of bacteria.

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131
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1answer
15k views

Do bacteria die of old age?

I know that the cells of mammals at least stop dividing when they are old, and then die a programmed cell death. Then other cells have to replace them. But in a bacterial colony, each cell ...
8
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2answers
3k views

How can E. coli proliferate so rapidly?

The E. coli has a genome with approximately 5×106 bp. The main DNA polymerase involved in its chromosome duplication (DNA pol III , the one with highest processivity) can polymerize ~103 nucleotides ...
12
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1answer
648 views

What bacteria do unborn babies contain?

This Scientific American article states that "[human] infestation [by bacteria] begins at birth". This would suggest that unborn babies are free from any bacteria. However, if the mother catches a ...
10
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3answers
19k views

Why do Type II Restriction Endonucleases cleave at palindromic sequences?

Type II Restriction enzymes usually cut only at palindromic sequences. Is there any specific reason for that? Is there any advantage for bacteria if they cleave phage DNA at this type of sequence?
3
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3answers
272 views

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 ...
4
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2answers
389 views

Can an argument be made that humans are 90% bacterial?

On the blog, All about Scientist in Microword: Microbiology, I read the post We are 90% bacteria, actually, which says that humans are 90% bacterial cells. If this is the case, then why don't we ...
34
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2answers
14k views

What is the advantage of circular DNA in bacteria?

From what I understand, bacteria have circular DNA. What advantages does it have over linear strands like for eukaryotes? Do there exist bacteria with more than one ring of DNA?
18
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4answers
8k views

What causes the development of antibiotic-resistant strains of bacteria?

I understand bacteria have become resistant to antibiotics due to selection pressures, but how do resistant bacteria process antibiotics when exposed to it, compared to non-resistant bacteria. Also, ...
15
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1answer
8k views

Why does Penicillin only affect bacterial cell walls

I was quite fascinated by the feature Should Science Pull the Trigger on Antiviral Drugs—That Can Blast the Common Cold? in this month's Wired magazine. They explain that Penicillin is effective at ...
7
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3answers
2k views

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 ...
11
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1answer
547 views

What are the functions of magnetic bacteria?

I'm trying to understand why are bacteria "equipped" with magnetosomes ("intracellular organelles in magnetotactic bacteria that allow them to sense and align themselves along a magnetic field") and ...
15
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1answer
16k 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? ...
9
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2answers
3k views

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-...
6
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1answer
29k views

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 ...
4
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2answers
2k 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 ...
14
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2answers
81k views

How do prokaryotes perform cellular respiration without membrane-bound organelles?

In order to survive, prokaryotes such as bacteria need to produce energy from food such as glucose. In eukaryotic cells, respiration is performed by mitochondria, but prokaryotic cells do not have ...
11
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1answer
1k views

Why don't vaccines cause bacterial resistance?

Since bacteria can evolve to overcome antibiotic use, why wouldn't they be able to evolve to overcome antibody or cell-mediated immunity? (One possible explanation: antibiotics have only one target ...
7
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2answers
1k 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 ...
5
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2answers
288 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?
16
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1answer
1k views

Are the bacteria in the stomachs of unborn babies beneficial?

Babies are born with bacteria in their stomachs. I heard on The radio that when a child is given antibiotics for the first time unique bacteria in the stomach are destroyed and cannot be replaced. Is ...
14
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1answer
1k views

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 ...
11
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2answers
12k views

Why would taking antibiotics increase stamina and energy?

I often hear that people who are taking antibiotics experience wild fluctuations between feeling full of energy and completely alert but soon after feeling impossibly fatigued and sick. Does this ...
7
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1answer
1k 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 ...
6
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1answer
241 views

What is the advantage of using plant-derived antibacterials rather than bacteria-derived antibacterials?

So obviously we have a big problem with antibiotic resistance. Most of our antibiotics originate from bacteria themselves (or are synthetic variations on scaffolds which originate from bacteria). I ...
5
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1answer
1k views

What are the most important factors influencing a person’s gut microbes?

You are your bacteria! The probiotics and the antibiotics... There has been on going discussions about how our gut bacteria is important for a healthy lifestyle. Figure 1: Schematic diagram ...
5
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4answers
2k views

Can general soap kill bacteria?

I have read that general soap can kill bacteria by opening holes in the bacterial membrane. http://questions.sci-toys.com/node/90 However, I found some articles as well saying that it cannot. http:/...
19
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2answers
25k views

How does isopropyl alcohol disinfect less in higher concentration?

Isopropyl alcohol (2-propanol) can be used as disinfectant. For increasing concentration of it in water, the effect as disinfectant increases, and then decreases again. Typical concentrations for ...
6
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1answer
133 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% archae....
5
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3answers
4k 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
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1answer
7k 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+ ...
3
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1answer
429 views

What does completing the course of antibiotics accomplish?

This article from the WHO states: If you stop treatment early, there is a risk the antibiotics won’t have killed all the bacteria that made you sick and that it will mutate and become resistant. ...
2
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1answer
76 views

Have bacteria evolved antibiotic resistance in a laboratory setting?

Is it possible to breed a strain of bacteria in a laboratory setting so that it gains resistance to an antibiotic, replicating the kinds of resistance seen in wild, and has that been done?
2
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1answer
544 views

How does Vibrio cholerae benefit from infecting its host?

As far as I know, V. cholerae secretes a toxin called choleragen into the intestinal lumen which affects the intestinal epithelial cells causing release of Na+ and Cl- ions into the lumen and reducing ...
2
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1answer
80 views

How many diseases can be linked to disruption in the microbiome of a human?

I was listing to the radio and heard recent research found a link between children and higher cases of asthma when certain bacteria are missing from the microbiome. How many other diseases can be ...
2
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3answers
506 views

Could plasmids and conjugation mechanisms be used against antibiotic-resistant bacteria? [closed]

I'm surprised no one has mentioned something like this. Plasmids are often exchanged between bacteria, sometimes through conjugation. In particular, conjugation could be considered an "open-port" ...
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0answers
809 views

Were we able to create vitamin B12 in past?

All herbivores produce vitamin B12 de novo. Gorillas, for example, are "vegans" so I suppose some human ancestor was also herbivore. Have we ever been B12 self-producers? If so, why have we lost that ...
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2answers
237 views

How do I look for pathogen in water with a microscope? Is it possible?

I am a 9th grade student from Manila and we're currently working on an investigatory project. We want to know how effective SODIS or solar water disinfection is. The purification method claims to be ...
1
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4answers
224 views

Why aren't all infections immune-system resistant?

It's been less than a century since the widespread use of antibotics started, and already we're seeing bacteria that have evolved immunities to the antibotics we use. On the other hand, we've been ...
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2answers
169 views

“Most bacteria have at least one cell wall”

In the first answer to How do we find antibiotics? @Ashafix claims that Most bacteria have at least one cell wall Does this mean that there are bacteria with more than one cell membrane? Which are ...