54

It doesn't. Viruses don't "know" anything. Mutations occur at random. Most of them don't do anything, or have a slight negative effect on the ability of the virus to infect and reproduce. However, there are billions and billions of viruses. Once in a while a random mutation will offer a significant advantage like immunity to an anti-viral drug. The viruses ...


36

Bdellovibrio bacteriovorus (BV) “infects” other bacteria: Similar to a virus, BV attacks bacteria such as Escherichia coli (E. coli) by attaching to and entering its prey, growing and replicating within the cell, and then suddenly bursting out, releasing its progeny into the surrounding environment. — How bacteria hunt other bacteria


31

My (limited) understanding is that it is quite hard to avoid killing some bacteria even with very gentle physical manipulation. On the other hand, it is quite hard to use physical force to achieve reasonable level of sterilization. Let's bring some examples with a few (hastily found) references. Pressure My guess is that most examples the OP mentions (hit ...


28

An autoclave can sterilize both solids and liquids, whereas an oven with no pressure control is typically not suitable to sterilize liquids. Not only do you need to heat the chamber to 121°C, but you also need to make sure that the things you are trying to sterilize are not degraded by the treatment. For dry objects (e.g. glassware) you could heat the ...


19

There are plenty of physical or mechanical methods of killing bacteria, but most are used in conjunction with other agents and probably don't qualify as "blunt force trauma". For example, beer distributers might snake a brush through a keg line to disrupt any bacterial biofilms before flushing them out with disinfectant. Similar logic applies to ...


17

The quick answer is: Yes, it can cause harm. Think about it...The septic system (both the tank and your "drain field") rely on bacteria, and antibacterial soap is not designed to kill only specific species of bacteria. In other words, antibacterial soap can kill a whole range of bacteria, and that certainly includes the bacteria needed in your ...


13

Looks like you may have Monilinia fructigena, brown rot, or at something similar (possibly also called brown rot, but from a different species). This pattern isn't special to quince, but to this fungus. The formation of these rings is called "zonation", and the concentric rings are from areas of growth that are primarily spore-forming versus not. ...


12

This is molecular evolution and is completely undirected. Mutations happen all the time, most of them disappear without anyone noticing, since they have no evolutionary advantage to permeate. This is different when you treat the cells and put them under an evolutionary pressure. Under this conditions, mutations which affect the mechanism of the drug (as ...


10

Note that a lot of the answer to this question hinges on what you mean by "infect". Bdellovibrios (as Laurel has already established that this does happen) do something that does look a lot like infecting eukaryotic cells- but it is still spoken of as "hunting". Why? I am not sure. There are lots of different ways that bacteria can have ...


8

There's Trichoplax adhaerens, a Placozoa, made of a few thousand cells. Then there is Dicyema japonicum, a simple mesozoan, made up of 9 to 41 cells. Arguably, the simplest multicellular organism is the algae Tetrabaena socialis, whose body consists of 4 cells. Then, there's the parasitic Myxozoa which have 7 cells.


7

Summary: They Don't. Long explanation: Mutations happen at random. A series of factors can lead to the perceived notion that the mutation was intentional. The mutation can be harmful, beneficial, or neutral. Harmful: We don't see the harmful mutations as these individuals don't proliferate. The mutant individual just dies off without passing their ...


7

They seem to be rotifers, the fuzzy (supposedly rotating) mouthparts are part of what convinces me. The behavior you mentioned of latching on the moss with their 'tails' is also a characteristic behavior of rotifers. They are also able to retract their bodies just as you mentioned. Here are some images of rotifers that might support the argument. I am least ...


6

It is plausible but by no means established that antipyretics (fever suppressors) in particular could increase the duration of infection/symptoms, because fever is part of a functional immune response. From Graham et al 1990 (a small [n=56] randomized trial of the use of antipyretic pain relievers in volunteers experimentally infected with rhinovirus): ...


6

Yeah, holes seem to happen in leptomyxa: L[eptomyxa] reticulata is an edaphic protozoan and a predator of bacteria and amoebae. [...] The plasmodium is very polymorphic; its size varies between 50 .mu.m and 1 cm. It generally spreads in the form of a very thin transparent protoplasmic layer. It may have the shape of a full blade, sometimes perforated with ...


6

The bacterial cell wall is quite porous, and is not considered a permeability barrier for most small molecules. It mainly functions as structural support and to resist turgor pressures. The average pore size of relaxed peptidoglycans were measured to have a radius in a range of about 2.0 to 2.5 nm, regardless of thickness (i.e. Gram + and Gram - bacteria ...


6

Answer No. There is ample evidence that: Most non-extremophilic bacteria grow over a broad range of external pH values, from 5.5 – 9.0, and maintain a cytoplasmic pH that lies within the narrow range of pH 7.4 – 7.8. The explanation for this is another matter, but, before discussing that question there are two points of possible misunderstanding in the ...


6

I'm guessing at the motivation for your question -- In the evolutionary history of eukaryotic cells, mitochondria were once free-living bacteria. What prevents them from acting as intracellular pathogens and replicating out-of-control? Yes, by endosymbiotic theory 1, mitochondria were once free-living prokaryotic organisms. This is evident because they ...


6

This nematode always has either 959 or 1031 cells. https://en.wikipedia.org/wiki/Caenorhabditis_elegans


5

The World Health Organization states[*]: 1:100 dilution of 5% sodium hypochlorite is the usual recommendation. Use 1 part bleach to 99 parts cold tap water (1:100 dilution) for disinfection of surfaces. They say most household bleach solutions contain 5% sodium hypochlorite (50 000 ppm available chlorine), which does seem to be the typical concentration ...


5

I have also been frustrated by use of percentages in protocols when making dilutions of stock bleach. It's helpful to look at the product labels, as they often have dilution factors for different uses as well as concentrations in parts per million. I have a bottle of Clorox brand concentrated bleach sitting next to me, and the label says this solution is ...


5

Virus cannot reproduce on their own; they can only reproduce by taking over a cellular organism. For this reason, the idea of a 'virus colony' does not make sense. You could have a colony of mold or bacteria that is infected by a virus, but a virus by itself could never create a single offspring, let along a macroscopic colony. If there were some type of ...


5

These aren't technically extremophiles, but one paper identified twenty species of bacteria that grow under a low pressure, mostly CO₂ atmosphere1. One relatively well studied species is Serratia liquefaciens (a Proteobacterium) that has been shown to grow under low temperature (0 °C), low pressure (0.7 kPa), and anoxic, CO2-dominated atmosphere-...


5

First of all, let’s consider your Methanosarcina scenario in specific. Methanosarcina with those properties are still around. So, there is no reason to expect that introducing some ancient Methanosarcina into a suitable environment today would do very much – as they should already be there. Any existing (large-scale) environment providing a niche for ...


4

Short Answer: Probably the most widely accepted (though certainly not fully accepted) theory of animal evolution is called the Colonial theory. According to the Colonial theory of animal origins, the earliest animals (i.e., sponges) seem to have arisen from colonial protists called choanoflagellates forming an invaginated hollow, spherical colony. ...


4

One way to identify mechanisms by which the body tames the microbes in the mouth is to observe what happens when those mechanisms are impaired: Deviation from symbiosis among the bacterial community leads to “dysbiosis”, a state of community disturbance. Dysbiosis occurs due to many confounding factors that predispose a shift in the composition and ...


4

Isolating virus particles is important for accurate genomic sequencing, which in turn enables study of mutation rates and determination of hotspots, locations in the genome where mutations occur at higher rates: “Sorting individual viral particles makes it possible to identify and sequence the genomes of viruses one by one,” states Òscar Fornàs, head of ...


4

2019-NCoV was first cultured by a Chinese group, as published here on January 24. China has not shared samples, but did share sequencing data in the linked paper and via GISAID. The Australian group at the Doherty Institute hasn't published yet, but did put out a press release today (January 29), and appears to be the first group outside of China to have ...


4

The short answer seems to be "yes", you can get single cells that are toroidal (donut-like) in shape. This seems to be done in the lab by various manipulations. This was first done in 1961. Notably, the cells in question seem to be eggs or single cells of multicellular organisms. Update: see @Fizz's answer about natural occurrence of holes I am guessing ...


4

E. coli and other bacteria metabolize tryptophan into odoriferous skatole and other indole compounds. If you're culturing these organisms in medium that contains tryptophan, that may be what you're smelling.


4

Yes of course. While you can't swing a blunt object comparable in size to humans at something many orders of magnitude smaller to kill it. You can use something like an ultra sonicator, which swings a small blunt object at --you guessed it-- very high speeds to generate lots of shear forces in a liquid culture. Usually these instruments are not meant for ...


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