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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Why is triclosan not considered an antibiotic?

Triclosan is a chemical often referred to as a "biocide" instead of an "antibiotic". However, its mode of action seems to suggest that it is an antibiotic. Triclosan binds to bacterial enoyl-acyl ...
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Favored Conditions of Bacterial Growth

I have read that bacteria "thrive" in warm places. Naturally, I am very interested in why this is the case. Humans for instance thrive also in relatively warm conditions if it's too cold or too warm ...
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Why a particular species of bacteria give rise to particular type of colony? [closed]

Bacterial colony varies in form, elevation, margin, opacity, chromogenesis etc. What gives definite character to a colony and what is the source of all the diversity? Is the reason similar to that of ...
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Why do cell membranes have a lipid bilayer?

Many cells have a cell membrane composed of two layers of lipids, why is it two layers and not just one? What purpose do the membranes serve?
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60 views

What are the differences and similarities between fimbriae and adhesins in microbes adherence factor?

Adherence factors in microbes is to attach to a host cell or to an extracellular matrix. So what is the difference and similarities between fimbriae and adhesins?
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45 views

Why do some bacteria have an asymmetric replication?

Our teacher said that Bacillus subtilis has an asymmetrical replication fork. I know that this happens only in some strain of the bacteria . She asked us to find an explication for this mechanism , ...
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1answer
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Why would a bacterial population show initial growth when it is in unfavorable growth conditions?

This figure shows the anaerobe E. faecalis grown in aerobic conditions, E. coli grown in restricted conditions that are not specified. Why do they show an increase in abundance initially? The black ...
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What exactly are polyphenols and what benefits do they provide to humans?

I say somewhere that they are antioxidants, but I was wondering if the two terms are synonymous or if that is just one of many things polyphenols can do.
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Why is 70% ethanol preferred for aseptic techniques?

Are other concentrations (say 80%) less effective,or is this just for convenient manufacturing? Is the concentration chosen only because it is less volatile than 100 percent ethanol and hence safer?
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337 views

What does “cellular” mean in this context?

I came across a confusing word when I was reading a Scientific American story, “Controversial Spewed Iron Experiment Succeeds as Carbon Sink” (by David Biello). It goes like this: “One key to the ...
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Which Lactobacillales (Lactic acid bacteria — LAB) strains are capable of degrading starch?

I've been researching bacteria strains but am having trouble finding amylolytic LAB strains with amylolytic and lactic acid producing character. The only species I've found, that are capable of ...
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172 views

Why does sulfonamid not inhibit the growth of Rickettsia?

Sulfonamid is an antimicrobial agent, why has it no effect on the growth of Rickettsia?
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1answer
65 views

Why don't bacteria eat food leftovers?

I have thrown a dirty spoon after eating some pasta into one of my desk drawers (doesn't do me much honor). It stayed there for around a year. My house is warm and I think there is enough humidity for ...
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51 views

Plasmid choosing

To design a experiment in feeding of C. elegans. It has to choose a plasmid vector to insert the gene of interest that can feed to C. elegans. Many paper are using pL4440 for the feeding vector, ...
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3answers
120 views

Does a microwave oven disinfect food?

Imagine I am preparing food, just about to put it into a microwave oven, and some of it falls on the floor. Assuming it got some bacteria or other organisms (viruses?) on it, will the microwave ...
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19 views

Symbiosis of Pseudomonas Fluorescens

Have a modest background in molecular biology and presently considering a project that requires some knowledge of botany. Specifically, I seek details on the epiphytic relation between the microbe ...
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2answers
52 views

Bacteria Replication

I learned this at a lecture, but somehow I have trouble in understanding this. It is said that the bacteria such as E.coli need 20 minutes to divide, but its chromosome require 40 minutes to multiply. ...
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How can Valonia ventricosa cells get so big?

Valonia ventricosa are single celled algae that range between one and few centimeters. In rare cases they can reach sizes exceeding 5cm. They range from grass green, to dark green, and some are even a ...
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1answer
51 views

How can E. coli affect C. elegans expression?

Plasmids can be transferred to E. coli. These transformed E. coli can be fed to C. elegans to silence its gene expression by RNAi. How can E.coli release RNAi to C. elegans? Even if we assume E. ...
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Counting of surface bacteria in real time

I'm fairly new to microbiology (okay, I'm forced to look into it for a group project). What I'm looking for is a way to quantitatively get an estimate of the number of microbes (bacteria and/or ...
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Why are viruses considered microbes?

My question is simple. Why is a virus considered a microbe? Considering a microbe is considered to be a "living" unit of life, which viruses are not.
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Nucleoside analogs that cause mutation

I'm confused with this explanation in my book: 2-aminopurine is incorporated into DNA in place of adenine but can pair with cytosine, so an AT pair becomes a CG pair. This sentence seems odd to me. ...
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25 views

Is there a good easy protocol for extracting proteins(enzymes) from fungal mycelium?

I quantify the enzyme (polygalacturanase)activity by DNSA method.To determine endo-polygalacturonase activity I'm searching for a good easy enzyme extracting method.Any suggestions for a suitable ...
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1answer
625 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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“Antibiotic resistance” equivalent in archaea for selection during cloning

I'm beginning to work with halophilic archaea and I'm trying to figure out a good way to select for cells that have taken up a plasmid. Obviously, one can't use antibiotic resistance since they are ...
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28 views

Enrichment of slow growing microbes: Large Test Tubes as an alternative?

Well, i would like to enrich bacterial and archaeal ammonia oxidisers from soil samples using Minimal Salt media. They are slow growing microbes. I would like to enrich them with the aim to produce ...
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1answer
548 views

Can the RNA in the HIV virus make viral enzymes without entering the nucleus?

If the provirus was not formed yet, can the virus make viral enzymes? (I know that it already has some, but supposing it doesn't)
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Can ampicillin resistant bacteria survive penicillin plate?

in my molecular bio class we were asked a trick question: If the bacteria has a plasmid with that grants it ampicillin ressistance, can the bacteria survive if placed in penicillin? I gave it a ...
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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? ...
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1answer
22 views

How can I interface cAMP signal or membrane potential from slime mold to an electrode?

I am very much interested in measuring cAMP (cyclic adenosine mono phosphate) signal and membrane potential from amoeba. Since I want to try this as a hobby, what are the basic steps I must do to view ...
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What's the aim of genetically modifying of foods/organisms?

On news, articles etc. experts talking about Genetically Modified Foods and Organisms often mentions about their disadvantages like, their potential to harm human health allergies may become more ...
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31 views

Soy kefir that never revitalises in animal milk

If I have kefir grains from goat and I make soy kefir and never revitalise the kefir grains in an animal milk, will that bacteria still be beneficial for the gut? What type of bacteria does it make? ...
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1answer
94 views

Reasons for the HIV-1 epidemic

So, the HIV-1 jump to humans occurred as early as the 1920s, but the AIDS epidemic didn't start until the early 1980s. Some things I don't understand about this: Why the delay? What is needed for a ...
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73 views

How do single-celled predators chase other cells?

From my understanding, single celled organisms have been seen avoiding, and chasing, potential food or other organisms. How do they accomplish this? They do not have eyes or ears or a nervous system. ...
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Ways to fight black mold

Is it possible to introduce a microorganism to a colony of black mold that will kill off the black mold entirely and permanently? Is there a common microorganism that likes to eat them and is harmless ...
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Are all pathogens parasites?

If parasites are organisms that feed on other living organisms, then aren't all pathogens parasites? I've emphasised on 'feed' because I guess the pathogens just eat us (i.e. take nutrients to ...
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124 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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Can mutation rate be increased for instance by mutagenesis targeting the DNA polymerase?

I am studying a non-cultivable bacterium living in an insect host, and I would like to generate some random mutants of this bacteria while preserving the insect. I am wondering if one way to do so ...
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160 views

How much salt [NaCl] is too much in DNA precipitation?

In DNA extractions, how much is too much salt in a CTAB extraction buffer? Protocols hover around 2.5 molar; if you go over this (e.g. 25 molar), will you saturate your solution, and precipitate the ...
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Why lab technicians use indirect (antibody reaction) method for diagnosing?

In microbiology we have two types of microbial diagnosis. The direct method is where we detect the invader's DNA, Antigens or culture to see the exact pathogen while the second, indirect, method is ...
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Why do kefir grains stop growing in soy milk?

Kefir is a fermented milk drink made with kefir grains. It usually is prepared by inoculating cow, goat or sheep milk with kefir grains. I would like to prepare the drink with soy milk, which worked ...
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Why does milk contained in cartons of milk expand?

In the morning, I went to the fridge to drink some chocolate milk. At night, when I took out the same carton of milk, the packaging seems expanded, like some kind of air is inside. Explain please !
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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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1answer
50 views

Spatial learning in microorganisms

Has there ever been an experiment performed that demonstrated a form of 'spatial memory' in a unicellular organism? I'm imagining something analogous to the classic 'rat in maze' experiments, but ...
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1answer
102 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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1answer
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How does botulinum toxin enter the blood stream from the digestive tract?

To my understanding, large polypeptides such as botulinum toxin cannot pass the intestinal lining intact. How, then, can it enter the bloodstream and cause botulism poisoning?
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Why does bacillus thuringiensis produce bt toxin?

Background : B.thuringiensis produces an inactive crystalline toxin during sporulation which when ingested by an insect, gets activated and causes pore formation in gut , subsequently leading to death ...
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1answer
169 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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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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Autotrophic and heterotrophic organisms in anaerobic condition

Can both heterotrophic and autotrophic organism survive in anaerobic conditions? If an autotrophic organism does not produce carbon dioxide but requires oxygen, it should not be present in anaerobic ...