Questions tagged [microbiology]

Microbiology is the study of extremely small organisms. This includes organisms like bacteria, fungi, protozoa, and viruses.

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Cell Size and Morphology of Microalgae under Wastewater

Hypothetical situation ahead, I am just curious whether the cell size and cell morphology of microalgae changes when it is under the influence of wastewater. For instance, mixing the microalgae ...
Kris's user avatar
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Why do we choose to use agar instead of agarose in various microbial applications?

When performing gel-electrophoresis we always use agarose. Is there a reason we can't perform it using Agar? And in microbial culture Agar is commonly used as solidifying agent, could this be replaced ...
Jayanth Vegesna's user avatar
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Does inoculum volume affect spread plate outcome?

Background The spread plate method is a technique used in microbiology to enumerate and isolate bacteria or other microorganisms present in a sample. It involves evenly spreading a liquid sample ...
Freezing Soul's user avatar
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What is the genus of this fungus?

I'm struggling to identify this fungus. Is it Aspergillus sp. or Penicillium sp.?
arsy's user avatar
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What distinguishes a colony from multicellular organism?

I would like to inquire what made biologists conclude that colonies such as the famous Volvox is an organism constituted by independent cells as opposed to a multicellular being. I read that it has ...
Jj Luntayan's user avatar
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1 answer
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Extremophile hunting and identifying unknown microbes

I'm going extremophile hunting! We're doing a trek by boat between some islands with semi-active volcanic terrain to try to document some interesting species, and running into a problem I've never ...
TheEnvironmentalist's user avatar
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1 answer
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Can placing a culture plate upright introduce contaminants from the lid?

Discussion I have developed a habit of keeping culture plates always inverted, especially those of non-selective media. This precaution is followed after the poured plate is placed inverted in the ...
Freezing Soul's user avatar
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1 answer
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Does sunlight interfere with the efficiency of compound light microscope?

I have access to an olympus bx41 microscope. The table on which sits the microscope is in front of a large window and unfortunately no curtains are available. I'm starting to relate that whenever the ...
Freezing Soul's user avatar
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Why did a resazurin broth bottle turn pink immediately after being inoculated?

I have lawn cultures of aerobic bacteria kept at (2-8 °C), which I am trying to revive since they were kept longer than recommended. First, I tried to incubate a broth culture inoculated with a ...
Freezing Soul's user avatar
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What is the optimal pO2 concentration for automated reactor batch mode EColi expression?

I am wondering what is the optimal pO2 level for an reactor based expression? All protocols I have found indicate for E.Coli pO2 levels just bigger 20%. So, I am wondering what is the optimal level? ...
raptorlane's user avatar
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Can Gravity convection incubators negatively affect the growth of strict aerobic bacteria?

Background Gravity incubators rely on natural convection for heat distribution. There is no fan or blower system, and the heat rises from the heating element at the bottom of the incubator. https://...
Freezing Soul's user avatar
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Can a gene transfer from a plasmid to a bacterial chromosome?

Plasmids are involved in providing resistance to antibiotics. So, can that gene or any other gene transfer from the plasmid to the bacterial chromosome? Is there any chance where antibiotic resistance ...
Amit Kumar's user avatar
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Storing bacteria in a dry, room temperature long-term storage whilst maintaining viability

I'm quite new to biology, but I'm wondering if there are any methods of storing bacteria in long-term, dry conditions with no climate control. Perhaps they could be dormant in a powder or granule-like ...
Lee's user avatar
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Storage of bacteria in MgCl2 at 4 degrees

I have a small question to which I am unable to find a proper answer. Will bacteria in a MgCl2 buffer (or similar solution) at +4 degrees Celsius survive storage for 1-2 days? Or will they die? What ...
Dunois's user avatar
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How can one store non-sterile culture media in dissolved form in the refrigerator?

How do I store non-sterile culture media in dissolved form in the fridge in a clean but non-sterile container? The powder of the media (Broth, Nutrient agar, MAC, or MH agar) will be put in a glass ...
Freezing Soul's user avatar
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How do i create sustainable readily available stock cultures to act as Gram stain controls?

My investigation on the matter Ref #1 Staining known Gram-positive and Gram-negative organisms on either side of your unknown organism act as positive controls for your technique. (Microbiology ...
Freezing Soul's user avatar
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Can a non-pure culture be used for reliable rapid phenotypic diagnostic tests?

Can a non-pure culture be used for reliable rapid phenotypic diagnostic tests (e.g. catalase, oxidase & gram stain)? "Slide Test Method Obtain a pure culture of the organism to be tested. ...
Freezing Soul's user avatar
3 votes
1 answer
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Why are my bacterial smears disappearing?

I'm trying to inspect simple stained bacterial smears. But my smear suddenly disappears after a successful inspection with the oil immersion lenses. The background can become too red (the color of the ...
Freezing Soul's user avatar
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What could be the cause of strange brown discoloration around some bacterial strains' colonies on macconkey agar?

Acinetobacter Unknown (Yellow TSI, Oxidase negative, Catalase positive) Unseeded plate My only guess is that the initial pH of the poured agar is too acidic (too red), so any alkalinity is more ...
Freezing Soul's user avatar
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1 answer
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How do microbiologists decide whether two morphotypes on the same plate belong to the same strain?

Background Colony: A colony, in microbiology, is a visible cluster or mass of microorganisms (such as bacteria or fungi) that has grown and multiplied on a solid agar medium. Each colony represents a ...
Freezing Soul's user avatar
1 vote
1 answer
50 views

Risk with cultures taken from stagnating water?

Necessary foreword: I'm an amateur and just starting with microscopy and microbiology. Wanting to observe some protozoa, I collected samples of dirt and water from some pools here in the city and ...
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Which species of iron-reducing bacteria are hyper-sensitive to copper?

I would like to know which species of iron-reducing bacteria are inhibited in their iron metabolism by a copper concentration of less than 500 nano moles per litre. Searching the internet, I can only ...
Shaun Ross's user avatar
1 vote
1 answer
135 views

Is there a reliable method to determine if heat fixation was inadequate before proceeding with further staining steps?

Background Heat Fixation: Heat fixation is a technique used in bacteriology and other biological sciences to affix bacterial cells or other microorganisms to a microscope slide. This is achieved by ...
Freezing Soul's user avatar
2 votes
2 answers
44 views

Prevention of disease spreading in animal kingdom

It's my first question on here, so I'm not sure If my question fits the theme. Please refer me to the appropriate one, If I have made a mistake. So a question that I wanted to ask has to do with ...
Đumić Branislav's user avatar
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Can I reuse agar in Petri dishes?

Can I simply re-melt agar in a contaminated Petri dish to use it again? I've tried searching for the answer on the Internet, but I was only able to find information about reusing Petri dishes ...
Karabin's user avatar
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1 answer
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What is the approx. diameter of a completely "folded up" human DNA molecule, in inches?

The human DNA molecule would be about 6ft if stretched out to a straight line. I'm curious what the diameter of the DNA molecule normally is when it is "all scrunched up" or "bundled&...
Doug Null's user avatar
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1 answer
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Concentrating cell concentration after subsampling

I need some help with regards to a concentration correction. I am measuring how many cells detach from a rock vs sonication time. Becuase I start from a rock, I cannot make aliquots and measure ...
Franco Grosso's user avatar
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How can one use motility testing as a practically reliable test for organisms identification in bacteriology?

Background information: The motility test is used to determine whether an organism is motile or non-motile. There are three types of bacterial motility *: Active movement: true motility that we are ...
Freezing Soul's user avatar
1 vote
1 answer
64 views

Can single-Use Gloves carry bacteria on their outer surface?

In bacteriology, can I touch items (e.g. oxidase discs) with my gloves not fearing to contaminate these items? Are these gloves (e.g. Disposable nitrile gloves) made so that bacteria can't adhere to ...
Freezing Soul's user avatar
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0 answers
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DnaA binding energy to E coli genome

I have been told that DnaA binds strongly to DnaA boxes on the E coli genome, but binds weakly to 8 out of 11 sites near ori. I want to know more quantitatively what strongly and weekly mean. Are ...
stochastic's user avatar
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What's the grade of D-glucose that can be used in glucose assimilation test in bacteriology?

Background information Carbon assimilation test is based on the ability of a bacterial species to utilize an organic compound (e.g. D-glucose) as a sole carbon source. This means that for carbon ...
Freezing Soul's user avatar
1 vote
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Minimum growing conditions of a given plant

Micro-algae are organisms that can grow in aquatic environments and use light and carbon dioxide (CO2) to create biomass. Researches showed that Micro-algae biomass can be used as bio-fertilizer. My ...
Wissem Boujlida's user avatar
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Resazurin not turning pink

I want to add resazurin to my media as an anaerobic indicator. To my understanding, the resazurin is blue when first added to the media, then turns pink after autoclaving, and finally it turns ...
David Madrigal Trejo's user avatar
2 votes
0 answers
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Unidentified Fish-like Microorganism from pond water

I was looking at my friends pond water and saw several Daphnia. As I was searching, I noticed a Pliomate Rotifer and some other unidentified Microorganism. It looked almost like a micro fish, with a ...
Ginger's user avatar
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2 votes
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Are bacteria repelled by self-lysis products?

Intuitively, it seems like treating your own lysis products as chemorepellants would make sense, since getting away from a place where your kind are dying would be a Good Idea, but I can't find any ...
Hattress's user avatar
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Can you perform D-glucose assimilation test for a bacterial strain without API kit?

Background facts: Glucose assimilation test is based on the ability of a bacterial species to utilize glucose as a sole carbon source. The test is designed to determine whether the organism can use ...
Freezing Soul's user avatar
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0 answers
326 views

Why is mold able to survive inside LCD screens?

A week ago i was cleaning and refurbishing an old laptop and i noticed it had spots on the screen. I was able to clean off some of the spots but others were impossible to remove. For a moment i ...
Maurice's user avatar
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How much thermal energy is released by the anaerobic fermentation by C. Lungdalii grown on hydrogen

For example, reaction H2+CO2 + X --> acetate + biomass. How much thermal energy is released kJ/g acetate. Purpose is to calculate the heat balance of reactor. Thanks! Dorian
dlight's user avatar
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1 answer
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Need help identifying this microbe

Sorry for the bad image, we don't have a camera hooked up to our culture room microscope yet. But Has anyone seen these kind of (what I'm assuming are) contaminating bacteria before? We see these from ...
user74814's user avatar
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0 answers
29 views

Conjugation of bacteriophage transduced genes

wonder if it is proven that bacteria can spread genes acquired by transduction or infection with a temperate phage by conjugation or transformation? Can you give me link to article that discuss this ...
Arwagolllon's user avatar
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0 answers
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How to Resuspend cells at cell density of 8 log CFU/ml of bacterial culture whose CFU/ml i don't know at 600nm, also it doesn't grow well on MRS agar?

According to procedure after 24 hr growth of Lactobacillus delbruckii subsp lactis in MRS broth, I have to resuspend it at 10 raise to power 8 CFU/ml and then inoculate it further. But it doesn't grow ...
ANANYA's user avatar
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1 vote
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Endospores contact with surfaces

I am currently studying endospores-forming bacteria. To be specific B.subtilis. I noticed that the formed spores have strong contact "grip" with the surface it is forming on. For example, ...
Anwar Elhadad's user avatar
2 votes
1 answer
48 views

How can a layperson get their hands on a specific strain that's not readily available commercially?

I'm mostly interested to get my hands on L.plantarum D-103, but there are a few other strains as well. D-103 is e.g. mentioned here https://meridian.allenpress.com/jfp/article/80/10/1682/199965/...
Anton Rodenhauser's user avatar
0 votes
1 answer
37 views

How to figure out growth/culture conditions for a specific strain?

Specifically, I'd like to find out how to grow ME-3 L.Fermentum (DSM 14241) at home without any fancy equipment. What food does it need? Sugar? Lactose? Something else? At what temperature does it ...
Anton Rodenhauser's user avatar
2 votes
1 answer
44 views

What is the easiest way to determine the species of non-tuberculous mycobacteria?

We have isolated a mycobacterium strain from patient sputum using an NTM Elite plate. When inoculated into an MGIT tube, we observe fluorescence when observed under UV light, which means it is highly ...
Johan Wikström's user avatar
5 votes
1 answer
94 views

What's the purpose of using more than one culture medium for bacterial isolation?

What's the purpose of using more than culture medium for bacterial isolation? Why not use just one? If this is not generally used in isolation of various types of bacteria, I'm concerned especially ...
Freezing Soul's user avatar
0 votes
1 answer
953 views

What are these white, fuzzy dome-shaped contaminants growing on my LB agar plate?

We are attempting to extract bacteriophages from environmental samples. We recently had an issue with an unknown contaminant when trying to grow a lawn of M abscessus for a bacteriophage isolation ...
Johan Wikström's user avatar
7 votes
1 answer
422 views

Has there been evidence that there has been coevolution in E. Coli strains with the T4 bacteriophage?

According to Evolution of T4-related phages, there have been multiple instances of evolution in the T4 coliphages. Per the article, there are many T-even phages that have insertions from other ...
spaik's user avatar
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4 votes
1 answer
542 views

Doesn't pasteurization kill gut bacteria such as Akkermansia muciniphila?

I've recently watched two presentations on YouTube (this and this) about Akkermansia municiphila, a commensal bacteria that feeds on the mucus of the gut. What I find confusing is their claim about ...
Paul Razvan Berg's user avatar
5 votes
1 answer
594 views

Why does adding calcium chloride aid in bacteriophage infection?

We are attempting to isolate bacteriophages from environmental soil samples and most protocols recommend adding CaCl2 to the media to aid bacteriophage infection, even though they all recommend ...
Johan Wikström's user avatar

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