Questions tagged [microbiology]

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

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Can DNA rings, i.e. plasmids, form as Möbius strips?

I know that plasmids can be present in a coiled form, which keeps the DNA strands together when they degenerate, by forming catenases. I was wondering, however, whether it has been documented to ...
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How are logarithmic trendline equations used to determine antibody concentrations in ELISA?

For example, say you have plotted a standard curve and managed to obtain a logarithimic trendline equation like: y = mln(x) - b And you are working with data that includes: a) standards,their ...
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17 views

Where can I obtain Sputnik virophage samples?

I'm working on a project where I'm trying to use virophages as viral vectors in introducing CRISPR-Cas proteins into other viruses. I was wondering where I might be able to find replication-defective ...
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42 views

What makes iodine an effective antiseptic?

I'm thinking about tincture of iodine, potassium iodide (Lugol's), and povidone-iodine (PVP-I) specifically, which, as is my understanding, work by solubilizing elemental iodine in an aqueous solution....
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Why did isopropyl alcohol not work as a disinfectant for E. coli in this experiment?

I recently performed a lab to test different concentrations (20-99%) of isopropyl alcohol and its inhibition of E. coli growth. My control was an antibacterial disk, and what I did was I dabbed the ...
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Why does atrazine kill photosynthetic bacteria and not nonphotosynthetic bacteria?

Atrazine was found to bind to Qb, which is involved in electron transport to create ATP in photosynthetic bacteria. Why does this herbicide kill photosynthetic bacteria, while having little to no ...
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29 views

Which culture media is suitable for cheek epithelial cells?

A month ago, I tried isolating cheek cells from saliva and the experiment was a success, however, I was wondering if it is possible to cultivate these cells in vitro. I'd say it's possible, but I wasn'...
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33 views

Why is synthesis of tetanospasmin advantageous to C. tetani?

The tetanospasmin is a neurotoxin synthesised by some strains of C. tetani. It is the factor causing tetanus, but what is its role for the bacteria itself? I do not believe the main objective of C. ...
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24 views

Diffussion coefficient of blood

What it the diffusion coefficient of blood in, e.g. water? It is needed for microchannel length calculations I have found a bit different nubmers: 0.94 and 1.66 microns^2/ms, but not sure
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Is there any double staining method to visualise separate colour for plant tissue and fungal tissue?

Is there any double staining method for developing separate colour on fungal tissue and plant tissue when the said 2 types of tissues are intermingled? Unlike my previous question, this question not ...
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25 views

Species diversity in cheese and yoghurt?

There have been studies on the number of species on humans and in various other environments. I was wondering how many species including: viruses, bacteria, yeasts, and fungi inhabit ordinary farm ...
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53 views

Are olfactive indicators always the result of inadequacy in sanitation?

Question If you can smell the scent of food in a thoroughly cleaned container, does that imply trace amounts of food particles remain? Scope It goes without saying that our sense of smell is ...
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31 views

DNA replication in $ E.coli $

$ E.coli $ has circular DNA which I guess implies one strand forms the outer circle and the other the inner one. So, is there a way to know if the replicated DNA forms the outer or inner circle? In ...
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23 views

How is the right amount of nucleotides synthesised during homologous recombination?

I'm reading about homologous recombination in the context of double-strand break repair. It seems like the trick is that around the break, homologous recombination uses a template duplex to generate ...
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4k views

Why some eggs are bile stained?

Why eggs of some helminths( Diphyllobothrium latum, Trichuris trichiura, Ascaris lumbricoides etc) are stained with bile while eggs of other helminths( Hymenolepis nana, Enterobius vermicularis etc.) ...
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Trying to find the right plasmid expression vector for e. coli c600

I am very new to the concept of gene cloning and transformation. I am trying transfer the arenite oxidase gene cluster (9kb in length) to E. coli strain C600. I want the E. coli strain to express this ...
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87 views

What M9 stands for

Can anyone tell me what M9 stands for in M9 medium? I have tried googling but I still cannot find it.
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201 views

Virus plaque assay, pfu/ml calculation on plates with too little plaques formed

I am a student, so I hope it is okay to put this question here. I've done the virus plaque assay in a practical recently and have a few questions regarding the plaque count for pfu calculation. In ...
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39 views

Fluoroquinolone mitochondrial and genomic DNA adduct

What could be possible consequences of covalent bond mitochondrial and genomic DNA adduct by Fluoroquinolones, our study was done by Fluoroquinolone Toxicity Study NFP. All 50+ participates who took ...
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31 views

Can a plastic degrading bacteria project be recreated in a school lab environment?

I am looking for a science fair project and am wondering if this could be a good idea. I am in the 10th grade. I am not exactly sure of the materials needed since this is just the beginning stages of ...
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80 views

How do the bacteria producing bacteriocins protect themselves from it?

Whenever there is Col plasmid in a bacteria it will produce bacteriocins which will kill other bacteria around it. Why will the bacteriocin not kill the bacteria which has produced it? How does the ...
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95 views

Why Cerebrospinal fluid is not heated for VDRL?

For performing VDRL of serum , we heat serum to inactivate complement proteins which may otherwise interfere , but why don't we do same for CSF even though it too has complement proteins in it? Is it ...
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53 views

Is there a limit on how big a free living unicellular mono-nuclear organism can be?

When I looked for the largest protozoan I've found the name Syringammina fragilissima. According to wikipedia " .. Syringammina fragilissima, is among the largest known coenocytes, reaching up to 20 ...
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43 views

Using distilled water on sterile swab for collecting microbes on solid surfaces

I was wondering if it is acceptable to use distilled water on a sterile swab for the collection of microbes on a solid surface. - in this case, Salmonella and Shigella.
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26 views

What gives researchers a reason to test the Radiation Resistance of organisms?

I was reading about the Thermococcus Gammatolerans and its absurdly high radiation resistance, when something occurred to me. What reason did anyone have in the first place to subject this thing to ...
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563 views

largest and smallest gram positive, gram negative and fungal pathogens

As I stumbled through this question: A 16-year-old female patient presented to her family physician with a complaint of an abnormal vaginal discharge and pruritus (itching). The patient ...
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27 views

Bacteria utilize short chain fatty acid as energy source

I'm doing research about the short chain fatty acid producing bacteria. I studied 7 short chain fatty acid (acetic propionic butyric isobutyric valeric isovaleric and captionic). and I found that the ...
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66 views

Can different Chromobactierum strains have completley different colony morphology?

In the analysis of an unknown bacterial broth I observed a gram negative rod genus. Upon plating I observed small, dark purple and convex colonies; corresponding presumably to Chromobactierum. After ...
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26 views

How do (commensal and mutualist) microorganisms colonize the seminal vesicles?

Human's seminal fluid has it's own microbiome (Javurek et al. 2016). How do species of this microbiome (bacteria and eukaryotes) colonize the seminal vesicles? It is possible that different species ...
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Microbroth dilution

I have performed MIC test for fungi candida albicans, Cryptococcus neoformans and Aspergillus fumigatus in a 96 well plate by broth microdilution method by drugs Amphotericin B and fluconazole.....
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810 views

Has autogamy been observed in any animals?

By my understanding, reproduction that is sexual, but with both gametes contributed by the same individual, is not at all uncommon in the plant kingdom. But where, if anywhere, does it occur in the ...
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33 views

How would you find and cultivate specific forms of algae?

Knowing how simple and efficient it is to grow algae, I started wondering how a person would specifically isolate and grow different strands of algae. Say I walk to the closest body of water and took ...
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59 views

Exclusion Limit and permeability of outer membrane

According to this textbook: P aeruginosa, for example, which is extremely resistant to antibacterial agents, the outer membrane is 100 times less permeable than that of E coli.[pg.no 27] and then ...
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27 views

Does Antioxidant prevent oxidation that creates free radical?

I have already known that antioxidant can neutralize oxidant/free-radical, but i want to know if antioxidant can also prevent the oxidation or not. I want to know to how it works if antioxidant can ...
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41 views

Bioenergetics of bioconversions: is there a surplus of energy?

By bioconversion, I mean a microbial process during which resting cells are used in order to convert a substrate to a desired product, whithout cell growth. For example, in this paper, they used ...
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291 views

What are chromosome dimers and how do they relate to recombination?

I am reading the book Molecular Genetics of Bacteria 4th ed. and I don't fully understand the concept/visual representation of dimer chromosomes. Consider the following quote (pg 35): an odd number ...
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38 views

Maximum parsimony tree - Am I right, or is the correction model right?

Alright. Monday we have a test, and now I was making a practise test. We have to make a maximum parsimony tree. We must do that monday again, so I want to know if I am thinking wrong, or if the ...
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64 views

How do environmental conditions differ between nitrogen fixing bacteria and denitrification bacteria?

I am currently experimenting with aquaponics and need to better understand nitrifying and denitrifying bacteria. From my research it seems that both varieties are anaerobic. From an engineering ...
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33 views

Cows milk protein transferability through breast milk

I understand that cow's milk protein(casein) transfers through breast milk via the mother's diet. I'm looking for the process as in what hormone does it bind to to allow this process in some women ...
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145 views

Biological replicates

We are currently doing an screening where supernatans from a bacteria genus are tested againts a pathogenic bacteria cell culture in a 96-well plate where OD is measured each 2 hours. Each ...
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35 views

How could you measure the rate of light reactivity/ photosynthesis of a cell in a lab setting?

For a lab I must take Volvox protist cells and expose them to specific wavelengths of light. How would I know they're even reacting? The assignment I've been given does not explain what I should even ...
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What is the mass or range of weights of individual microbial spores and or cysts?

Also looking for the overall physical dimensions of spores/cysts. I am trying to estimate how much static charge a spore/cyst would require to overcome the pull of gravity.
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206 views

Phenol Red Broth question; what is point of broth without carbohydrate?

Without carbohydrate in the broth (some) bacteria would then degrade the peptone, which from its end products would increase pH and then turn zhe phenol red pink. So I think this is some type of ...
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816 views

Pigmentation in dermatophytes

Dermatophytes are cutaneous keratophilic fungi. They cause concentric skin lesions. As a sample, usually skin scrapings are collected. When viewed under the KOH mount, they appear transparent but ...
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Has anyone tried using luminescent conjugated oligothiophenes to detect cellulose in a microbial biomass? If so is it accurate?

I recently found this paper http://www.nature.com/articles/srep35578 which describes a "new" method for detecting cellulose. As I'm not an expert in the field I was wondering if other people have used ...
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What decides the nocturnal periodicity of microfilariae?

Microfilariae, which are the larvae of filarial worms show a nocturnal periodicity of entering into blood in south Asia and China. This coincides with the biting habits of its vector. The same very ...
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204 views

Why do fungi and bacteria have macroscopically distinct patterns of colonies?

Why do microbes, when incubated on an agar plate forms a distinct kind of appearance i.e., d shape of colony. Its kind of less unique in case of bacteria. Bacterial colony http://image.shutterstock....
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591 views

Wet weight measurements: Setting up cultures for measuring growth rate via wet weight

I have some isolates which I am trying to grow in some toxic leachate in order to measure their growth rate I also want to measure the growth rates of certain combinations of these bacteria. I've ...
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119 views

Why is Leptospirosis so difficult to catch?

I was on a small mammals training course and the professor was warning of the dangers of Leptospirosis. Apparently 5-40% of Rats have it and an unknown proportion of other animals. The warning sheet ...
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How common is it for environmentally occurring bacillus strain to contain some sort of plasmid?

I am designing a method for testing whether two new bacillus isolates, that are ionic silver resistant, store the silver resistance mechanism on a plasmid or on the chromosome of the bacteria. In my ...