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Questions tagged [microbiology]

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

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If I need to view 0.3 UM micrometers what X strength microscope do I need ? (Streptoccocus Mutans)

Would also be glad if you had more charters of bacterias/virus/parasite pictures and sizes. Also maybe if you have other microscope specification for viewing them clearly I am completely new to ...
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Why don't antiseptic agents kill 100% germs?

I've seen innumerable antiseptic, mouthwash, handwash advertisements that claim to be able to eliminate as much as 99.9% of all germs over a surface...but why not the remaining 0.1% (i.e- why can't ...
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Why does regular bread yeast fail to thrive in pond water?

I thought I'd try adding regular yeast to water taken from my 75 gallon pond, with the idea that the yeast would be a good "bottom of the food chain" kick start to feed the little beasties, along with ...
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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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Bacteriophage isolation

I have environmental water sample from which i want to isolate bacteriophages. I've try to centrifugate several consecutive times. I've try with different speed (13000g and 15000g) and different ...
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2answers
102 views

Storage of bacteria

Why are strains of bacteria stored when they are inactive (frozen)? What is the problem about storing growing cultures for long periods? Thanks guys!
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Who gives a newly discovered microbe its name?

Assuming a hitherto unknown microbe is found - who gives it its name?
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2answers
335 views

Are bacteria incapable of producing cytokines such as interleukins?

As far as I understand, bacteria cannot produce cytokines such as interleukins. However, I have not read an explanation as to why they cannot. Perhaps it has to do with an evolutionary limitation. Yet,...
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58 views

How effective is water purification by boiling?

Does boiling water kill all harmful bacteria, fungus etc from water, or it is just a myth and removes only few of microorganism?
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1answer
56 views

Is there a non-bacterial source of lipopolysacchrides

I am wondering if there are any other non-bacterial sources of LPS. To my understanding, lipopolysacchrides (LPS) are components of the outer leaflet of gram-negative bacteria, but are there any other ...
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1answer
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what are the ethical considerations when preparing a bacterial culture for testing antibiotic resistance? [closed]

I cannot think of any ethical issues associated with preparing a bacterial culture to test antibiotic resistance. The bacteria I am using is Bacillus Megaterium so its not pathogenic. Thanks in ...
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1answer
2k views

Do all parts of a plant contain the same type of cell?

I have only learned about the plant cell which is shown below. But plant stems alone are made up of different parts like xylem, phloem, parenchymatous cells, sclerenchymatous cells etc. Are all the ...
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Why would there be a spike in coverage within a gene in RNA seq data? [closed]

I'm looking at RNA seq data in Geneious for Salmonella typhimurium and I occasionally see a spike in coverage for a sequence of RNA within a gene. Why is there a section of the gene that seems to be ...
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Need help on identifying this alga

link No idea what this is, please help. Thanks!
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51 views

Please help Identify these algae [closed]

Found this algae in a small stony stream that feeds a medium sized river. I can not identify either of the filamentous algae in this photo
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1answer
142 views

Prokaryote or just a small worm

In the following photos can be seen a thread-like (almost like longkou vermicelli) things. At first I was convinced that it was cyanobacteria, however a classmate said it look more like a little worm, ...
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1answer
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What kind of microorganism is this?

It moves like a worm pretty much. I found it in a pretty big pond with brackish water. The water temperature was around 10 celsius. Here's a video of it moving
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349 views

Is abiogenesis possible today?

Life on earth started about 3.5 billion years ago. I would assume abiogenesis happened because the conditions were right. Would the current earth conditions allow for new abiogenesis and completely ...
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1answer
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BLAST 16s rDNA: Everything alligns to Bacillus sp

I'm trying to identify and isolate Pseudomonas and Bradyrhizobium strains from rhizosphere and endophytic compartments of a tree. I plated the strains on selective media (King's B. for Pseudomonas and ...
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1answer
317 views

How can a pathogenic bacterium be avirulent?

Streptococcus pneumoniae R6 is a pathogenic bacterial strain but it is avirulent. How can a pathogen be avirulent. What does it mean if a pathogenic bacterium is avirulent?
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314 views

What is meant by “complexity of carbon sources”?

My biology book states "life on earth depends upon carbon based molecules, most of these food sources are also carbon based. Depending upon the complexity of these carbon sources, different ...
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1answer
117 views

What sort of biofiltration is best for a small, portable, biofiltration unit?

I've been exploring the idea of a system to allow re-use (drinking) of RV greywater, or at least the freedom to dump in storm drains (I think the requirements are looser about this, but it still has ...
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2answers
618 views

What is this green micro-organism found living in water?

I study biology in France and experiment on water filtration with plants. I found that some chlorophyll-containing micro-organisms (about 10 micrometers in length) were raised in my basin. I can't ...
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106 views

Pelleting bacterial cells using centrifugation and getting proteins in the supernatant

Do significant amount of proteins from cells find their way in supernatant during pelleting? If the answer is yes then I see two ways in which protein can be in the supernatant . 1) Through lysis ...
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2answers
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Human Digestion of Cellulose?

Most animals can digest the cellulose in grass because of the anaerobic bacteria called Fibrobacter succinogenes living in their rumen (gut). The bacteria produces the enzyme cellulase and is ...
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1answer
634 views

What is an inclusion forming unit?

What is inclusion forming unit load? I found it when reading this article. What does this measure and what information can be gained form it? Does this represent the amount of bacteria within a ...
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2answers
298 views

Can living cells be imaged with electron microscopy?

According to this article from October 2009, http://news.mit.edu/2009/electron-microscope "Electron microscopes are the most powerful type of microscope, capable of distinguishing even individual ...
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1answer
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Location of microbes causing eliminated diseases

Do eliminated diseases like polio, smallpox etc still exist in locations they have been eliminated from or in the wild or did we just make them go extinct like the dodo?
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225 views

Does sunlight kill rotavirus?

Does sunlight Kill Rotavirus? Maybe freezing? Norwalk or similar. Its a practical question for bedding.
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1answer
112 views

What is sequential passaging?

I have read a journal that describes sequential passaging with the purpose of measuring resistance development in bacteria. I would like to know more about how the method works ie. what does "passage" ...
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0answers
104 views

In what circumstances is ATP the limiting factor in performance for unicellular organisms?

I am interested in how enhanced energy levels in cells can contribute to elevated performance levels. Perhaps there have been experiments where unicellular organisms, enriched with ATP, were able to ...
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1answer
56 views

Why has malaria only now started to develop resistance against artemisinin?

Why has malaria only now started to develop resistance against artemisinin, considering the compound has been in use for about two millennia in its herbal form in China? The WHO has reported: In ...
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1answer
138 views

Help with preparing Congo Red TSA

So I want to make Congo Red TSA. My instructor gave some hints but I still have some questions: I start by making two stock solutions: 20 mg/ml of congo red and coomassie in two different falcon ...
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1answer
69 views

A suggested ancestor of cyanobacteria consumed manganese. Why not magnesium?

Joseph Kirchvink and others have suggested a theory that a precursor to cyanobacteria consumed manganese (I believe in the form of Mn2+ dissolved in water). Why wouldn't dissolved Mg2+ work equally as ...
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2answers
3k views

Why should benzalkonium chloride (an antifungal agent) be used during your laundry machine's “rinse” cycle, not its “wash” cycle?

I'll first provide lots of background information. My actual question is at the very end. Background The spread of athlete's foot Athlete's foot is a fungal infection which is mildly contagious. ...
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Why did my isolation streak of an unknown organism on Mannitol Salt Agar turn yellow where there was no growth and magenta where there was growth?

I repeated a culture twice in an entry level microbiology class for our final lab project of culturing a provided unknown organism. One of the required tests on our dichotomous key was to culture a ...
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What is R.ornitholytica? Is it a misspelling of R.ornithinolytica or a different species?

I'm trying to find out which of these is correct, or whether they are different organisms: Raoultella ornithinolytica Raoultella ornitholytica I have come across ...
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1answer
1k views

Can i grow bacteria on potato dextrose agar?

I was wondering if potato dextrose agar was a suitable environment for bacteria. Does it have all the requirements bacteria need or is it limited? Specifically: Escherichia coli, Staphylococcus aureus,...
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297 views

Why are the most heat tollerant organisms prokaryotic?

Prokaryotic organisms are able to grow at far higher temperatures than are eukaryotes. Archaea are known to group, among some mesophiles, the most extremophiles organisms (es. Pyrococcus furiosus), ...
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Are acid-fast bacteria Gram-positive or Gram-negative?

Both procedures involve using a stain, decolorising agent, and then a second stain. I am tempted to conclude that acid-fast bacteria, which resist decolorisation (eg. by strong carbol fuchsin), also ...
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1answer
282 views

Positive control for microorganisms

I'm planning to test the antimicrobial activity of endophytic fungi (their secondary metabolites) against Gram-positive bacteria, Gram-negative bacteria, and one fungus (Candida). I was wondering ...
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1answer
168 views

Example of invertebrates that are attracted to heat?

I would like to test a device that outputs heat in order to attract schistosome parasites in water. However, I would like to use a substitute, since I cannot find schistosome parasites for sale. Are ...
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2answers
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Difference between Peptone, Peptide and Proteose

In my school textbook, it is given that Pepsin converts proteins to peptones, proteose and peptides. What is the difference between the three products? On googling the terms, the definition was ...
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3answers
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Food safety during roadtrips [closed]

I will be moving across the country in the coming weeks, and I have realised that I will likely have leftover perishable food in my apartment before I leave and I was thinking of trying to prepare ...
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1answer
668 views

How do aerobic Rhizobium bacteria survive in root nodules while fixing atmospheric nitrogen?

I read that rhizobium carry the enzyme nitrogenase, which is irreversibly damaged upon the exposure of oxygen. Inside the root nodule of legumes leg-haemoglobin keeps a microaerophilic environment ...
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2answers
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What kinds of bacteria live in water bottles?

I've always heard not to re-use disposable plastic water bottles. According to this Huffington Post article, the reason is because: everyday wear and tear from repeated washings and reuse can ...
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1answer
486 views

Mass production of bacteria

Is there a way to mass produce a certain species of bacteria? Answers I am looking for should not involve a Petri dish: I am only interested in protocols involving, perhaps, more efficient mediums to ...
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1answer
424 views

Antibiotic resistance of Staphylococcus epidermidis and S. warneri

I am looking for information regarding the antibiotic resistance of S. epidermidis and S. warneri, specifically against penicillin, ampicillin and tetracycline but to no avail. Are there any good ...
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0answers
59 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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1answer
206 views

Well Plate Method VS Kirby Bauer Method

Any pros and cons? One puts the test substance in sterile discs, while the other one puts it directly into wholes in the agar. Any thoughts?