Microbiology is the study of organisms that are too small to be seen with the naked eye. This includes organisms like bacteria, fungi, protozoa, and others.

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How can fresh cavities form at the margins of sliver amalgam fillings on teeth?

Silver amalgam fillings predominantly contain silver a known bactericidal agent and mercury which a known toxin and has bactericidal property. So how is it that the plaque bacteria survive near the ...
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181 views

Vigorous shaking for HFR interrupted mating

I am trying to reproduce E. coli interrupted mating using an HFR strain, and I read that the cultures should be vigorously shaken at times to interrupt the DNA transfer from the F+(HFR) donors to the ...
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Identify the pink mold infecting refrigerated lemons [closed]

I made lemon juice 6 month ago. I just washed the lemon using brush and then cut them into pieces. Then I put one layer of lemon in the bottle followed by one layer of sugar Again one layer of lemon ...
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Can Listeria monocytogenes endotoxin act as an A-B toxin?

I think no, but I am not sure since Listeria is Gram-positive and probably has lipopolysaccharide (exception among Gram positive bacteria). Can Listeria monocytogenes' endotoxin act like exotoxin ...
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DNA polymerase I exonuclease activity

Does DNA polymerase I in bacteria use forward or reverse exonuclease activity to remove RNA primers? One of my books says it uses 5' to 3', but another says it uses 3' to 5' exonuclease activity. ...
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Can a plate with incompletely filled LB agar be used?

I am falling short of LB agar plates and I have a plate with less LB agar poured. I meant, the plate is not fully filled with the agar (it was the last plate I poured the medium into). Some part of ...
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132 views

Consumption of NAD+ in glycolysis

Out of 10 steps in glycolysis, only one reaction- Glyceraldehyde 3-phosphate (G3P) to 1,3-bisphosphoglycerate (PGP), uses NAD+ and thereby producing NADH. Furthermore, this very step is solely ...
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Why do 6-8% of diphtheria patients do not develop natural immunity after being affected?

I am thinking of why some patients do not have natural immunity after exposure to the A-B toxin of diphthria. I think the A-B exotoxin is the key factor causing this disease and should trigger memory ...
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52 views

Why increasing the vector concentration does not increase the effeciency of bacterial transformation?

I was reading some old description of the protocols used for the transformation of bacterial cells. In the description I read that the transformation works best with low amount of DNA, and if we ...
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100 views

Is there a difference between drinking water straight from the tap compared to leaving it to sit?

An idle question - if a glass if filled from the tap and consumed immediately, it contains some dissolved oxygen from the physical process of moving through the pipes & tap. If left out ...
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350 views

What is “bacto” peptone?

Standard recipes for yeast medium often include "bacto-peptone". Is this the same as bacteriological peptone? Is there an authoritative source that spells it out?
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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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336 views

Factor causing Methicilin-resistance in MRSA?

I think the main reason is the natural selection that is causing methicillin-resistance. However, I am not completely sure what this means practically. Here, the original question: MRSA was isolated ...
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Is it possible for a person to become “reinfected” with the same strain of a virus?

If a person contracts a virus, viral conjunctivitis for example, is it possible for the individual to become "reinfected" with the exact same strain of the virus once the person has it treated and the ...
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186 views

What molecular processes are involved in pseudopodial extension?

I am curious as to the processes and mechanisms involved in the extension of pseudopodia in amoeba. How does the cell know and control the direction and extent of pseudopodia formation at a molecular ...
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960 views

“Acellular” designation for organisms

Why do some biologists refer to single-celled organisms such as Amoeba and Paramecium as acellular (i.e., without cells) rather than unicellular (i.e., one cell)?
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34 views

What is the simplest autotrophic cell?

Very simple cells, such as Nanoarchaeum equitans, require a host to provide certain essential ingredients for life. Complex life-forms (like humans) require a whole ...
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54 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 ...
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35 views

Microalgae without cell walls?

Most microalgae have rigid cell walls. Dunaliella Salina is a pretty famous example of an algae with no cell wall, but just a plasma membrane. Are there any other microalgae without a cell wall?. I ...
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66 views

Survival of streptococcus after my scarlet fever

I'm currently sick because of scarlet fever but I got treated with antibiotics. I know that after 1.5 day using antibiotics the streptococci I release at home are dangerous anymore. But my question ...
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66 views

Did the Britons 100 years ago have different intestinal flora and fauna?

Note: this is not a question about history, but about human digestive system over time :) I know a lot of colleagues who traveled for business trips to India. All of them caught terrible diarrhea ...
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234 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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168 views

By what mechanism is Streptococcus bovis acting as a risk factor for colorectal cancer?

Streptococcus bovis bacteremia/endocarditis is considered a risk factor for colorectal cancer. What pathophysiological mechanism may link the two together?
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502 views

How was the diversity between ethanol fermentation and lactic acid fermentation evolved?

Quite simply, some organisms metabolize glucose under anaerobic conditions via Glucose->(2) Pyruvic Acid->(2)Ethyl Alcohol. Some organisms, however, metabolize to lactic acid. When did such a process ...
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408 views

Can Naegleria fowleri enter through the eyes ( example rinsing/splashing eyes with water)

I understand that it primarily enters the body through the nose by by "feeding on the olfactory neurons in the nose" as answered here in a different question. Would the nerve cells in the eyes present ...
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Cellulose acetate membrane filters vs. glass microfiber filters

At equivalent pore sizes and pressures, which exhibits faster flow rates, cellulose acetate membranes or glass microfiber filters? I know cellulose acetate exhibits low protein binding, but what ...
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Regulation of V. cholerae virulence factors

So I know that several different environmental signals, such as pH, bile, and temperature, regulate virulence gene expression in V. cholerae. Specifically, they control expression of the genes ...
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309 views

For people who work in microbiology labs, what software do you use to manage your strains?

It's just a small microbiology lab that currently records everything on paper, and there's quite few mutants as well. Is Excel commonly used for this sort of thing? Or is there a better software to ...
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Highly spherical Radiolaria; does this image accurately depict the organism?

If I understand correctly, Cenosphaera spp. is a type of Radiolaria, which is a type of zooplankton. The following is an image of Cenosphaera spp. is from the supplementary material (Figure S2) of ...
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239 views

Short-term Lamarckism in asexual single cell organisms

I was reading through the Karr et al. (2012) whole-cell computational model. One of the things they did was to induce single-gene disruptions in their model. They observed several to be fatal, but: ...
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When and How do pacemaker cells develop during the cell aggregation process of Dictyostelium discoideum?

I was reading a paper by Tang & Othmer about oscillations and waves in Dictyostelium discoideum. Under certain condition like starvation period in the life cycle of a Dictyostelium discoideum ...
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83 views

E. coli not growing in liquid medium

We are regularly doing bacterial transformation and subculture from plate to liquid media to extract DNA. This usually goes very well and is straightforward, but occasionally, the colonies that grew ...
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Why do flagella form a bundle only when they rotate counterclockwise during chemotaxis?

During Chemotaxis in bacteria with flagella, the flagellar rotation dictates how the cell moves. If the flagella rotate counterclockwise, then they form a bundle at one end of the cell (---O) and ...
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What is a good source that will help me classify protists?

I am a 15 year old that enjoys looking at the micro world. The only issue that I have is that I can't find a good online source that will help me classify the name of the micro organism that I'm ...
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Can someone explain the color-changing unit (CCU) to me?

I've been physically carrying out serial tenfold dilutions on samples of Ureaplasma to work out the color-changing units (CCU). As a definition, the CCU is the highest dilution at which there is a ...
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Why HIV patients have greater virulence of M.tuberculosis?

I am reading Murray Microbiology book. Some facts M. tuberculosis is an intracellular pathogen. At the time of exposure, M. tuberculosis enters the respiratory airways and infectious particles ...
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336 views

What type of photosynthesis is performed by phytoplankton?

I am not a biologist, but I know there exist three variants of photosynthesis, namely C3, C4 and CAM. I would like to know what type is used by the ocean's phytoplankton? It might also be that ...
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244 views

Where would Saccharomyces cerevisiae be found in highest concentrations in environment?

I have bakers asthma specifically to 'Sc' yeast, and know to avoid bakeries, breweries, etc... I have figured out to not disturb rotting leaf piles, and fermenting bark mulch. Where else? What ...
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Why do slime molds pulsate when growing into their fruiting body?

An example can be seen in this Youtube video, where the slime mold pulsates as it engulfs a rock in order to form its fruiting body. Why does this pulsing happen?
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89 views

How small does a nanobot have to be to “swim through the brain” and access any neuron it wants to?

I read on this question What is in the space between neurons in a brain? that there is actually not much empty space in a brain. But my question is slightly different. Is there a visual demonstration ...
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Use of salt as preservative

I know that salt is used as preservative as it dehydrates microbes. Is there any other advantage like - altering pH or inactivating microbial enzymes ?
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202 views

How to learn biomathematics?

I'm currently an undergraduate math student and researching on the internet I discover that exists an area called "biomathematics". Looks so interesting. They use the graph theory and topology to ...
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38 views

Identification of black growth on onion skin

I have encountered this black-colored growth on onion skins a lot. It seems to develop over the course of weeks and I have rarely, if ever, encountered the material on fresh ones. If I peel the onion ...
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304 views

Anaerobic respiration choice in E. coli

Under anaerobic conditions E. coli has two options to generate ATP: fermentation (substrate-level phosphorylation), and respiration (proton gradient, chemisomotic phosphorylation). Which is favored? ...
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Can a fungus become resistant to a chemical such as Potassium Permanganate?

A friend used potassium permanganate solution to treat tinea on the hands/feet but after some initial success, the tinea seems to be making a comeback. Could the fungus develop resistance to potassium ...
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Why does the mixture of infant formula with saliva provide an ideal breeding ground for disease-causing micro-organisms?

From: http://www.nal.usda.gov/wicworks/Topics/FG/Chapter4_InfantFormulaFeeding.pdf Discard any infant formula remaining after a feeding. The mixture of infant formula with saliva provides an ideal ...
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853 views

Can Naegleria fowleri enter through your ear?

Is it possible to get infected with the amoeba, Naegleria fowleri, through your ears, or is the nose the only way it can enter to cause infection? How commonly is it found in your stool as well?
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What is the difference between a spore and a cyst?

Last year I read a course in biology. During that course I learnt that Protozoa like Lamblia intestinalis or Entamoeba hystolitica form cysts in unfavourable conditions. This year I read a course in ...
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What does it mean to perform in vitro experiments with mutant bacteria?

I came across the following sentence while reading the paper: Nanchen, Annik, et al. "Cyclic AMP-dependent catabolite repression is the dominant control mechanism of metabolic fluxes under glucose ...
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143 views

Do bacteria with capsular antigen always have a capsule?

Assume some bacteria have capsular antigen. Do these bacteria always have a capsule? I think not, I think the antigen only makes it possible.