123

This is a interesting question and for a long time it was thought that they do not age. In the meantime there are some new papers which say that bacteria do indeed age. Aging can be defined as the accumulation of non-genetic damages (for example oxidative damage to proteins) over time. If too much of these damages are accumulated, the cell will eventually ...


87

You are absolutely right, flushing down the toilet (or the sink) or simply throwing them into the normal waste doesn't work for biosafety reasons. And it is also not allowed, depending on the country you would do this in, this can lead to hefty fines. Biologically contaminated lab waste can be inactivated (=all potential dangerous organisms are destroyed) ...


37

So I think this is a more conversational kind of question. I will address some misconceptions you have, and I will try to keep it brief, considering the nature and depth of your question. One could comment on the question very deeply, so I'll stick to addressing some misconceptions. Can I tell whether my sandwich is contaminated for example? Usually you ...


36

The bacteria wouldn't see any benefit from the warm water in the ~30-60 seconds you're washing your hands, neither would hot water "sterilize" your hands at temperatures you could tolerate. The reason you wash your hands with hot water is because the hot water+detergent soap mix is better for removing oil and dirt than cold water+detergent, which is ...


36

There is little motivation right now for vaccination against plague because: Human infections with plague are fairly rare. A vaccine administered to the general populace would have to be very cheap and extremely safe to make it cost-effective and have a net benefit given the risks of plague are so low, and because Antibiotics are effective against plague - ...


36

As you could imagine, a systematic cataloguing of bacterial or viral flavor profiles would violate a number of biosafety protocols. However, in a laboratory setting, different bacteria definitely have distinct odors. In some cases, the odor is even included in guidelines for laboratory identification of an organism. However, that odor is typically not a ...


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


33

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 ...


32

Mainly cost/benefit analysis. Using vaccines has a cost, both in dollars and in risk. That cost may be very low (cheap safe vaccines, like measles vaccine), or may be relatively high (smallpox vaccine is relatively risky, with around a 1 in 300,000 chance of moderate to severe side effects); but there is always some cost. Vaccines may not have any ...


25

First, and I cannot stress this enough, you should not go seeking out human pathogens if you don't have the appropriate equipment to handle it at the right safety level. That goes for all pathogens, even ones you might find around your house. In a professional lab, you might get samples from collaborators, clinical samples, vendor, or really an number of ...


25

This virology site has a post about a 2017 paper about membrane-vesicled plasmids that act in ways that are theorized to be precursors to how viruses work: It is likely that the plasmid-containing membrane vesicles are precursors of what we know today as virus particles. It is thought that viruses originated from selfish genetic elements such as plasmids ...


21

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 ...


19

To address what seems to be the misconception underlying your question: Killing pathogenic bacteria is not difficult; killing them without harming their (usually human) host is. This is why antibiotics are so precious: They are drugs that affect only bacteria¹ – by exploiting properties that are unique to them. It is usually resistance to antibiotics that we ...


19

It's suspected that some protists (namely choanozoans and picozoans) are proper/direct "virus eaters" due to the size of their "eating apparatus" and scarcity of bacterial remains inside them (unlike viral remains), but the evidence is pretty recent; the (2020) study: used modern single-cell genomics tools to sequence the total DNA from ...


17

The main reason why alcohols (isopropanol and ethanol mostly) can be used as disinfectants is that they denature (bacterial) proteins. This is also the reason why they work on such a broad spectrum of microorganisms (bacteria, fungi, viruses), but not on spores, as these are better protected. The higher the concentration of the alcohol is, the faster this ...


16

There is already plague vaccine in use, which is only administered to lab workers working on Y. Pestis or people residing in areas affected with plague. (Via: https://www.cdc.gov/mmwr/preview/mmwrhtml/00041848.htm) Plague can also be treated with antibiotics if detected at earlier stage (such as streptomycin, ciprofloxacin, gentamicin or doxycycline). Very ...


15

You can find a detailed discussion of this topic here. Magnetic bacteria contain chains of magnetic crystals (magnetite or greigite) which cause the cells to be oriented in a magnetic field. It was originally proposed that magnetic bacteria use their magnetosomes to ensure that they swim downwards into the sediment (everywhere on earth, except at the ...


15

They're effectively immortal, albeit in a Phoenix-rising-from-the-ashes sort of way. In general, a bacterial cell will divide as soon as it's biochemically able to do so, leaving behind two daughter cells. Neither daughter cell is actually the same as the mother cell, so in one sense the mother cell will have "died". On the other hand, the daughter cells ...


14

Reasons for Bacteria with different shapes as given in Wikipedia/Bacteria: The wide variety of shapes is determined by the bacterial cell wall and cytoskeleton, and is important because it can influence the ability of bacteria to acquire nutrients, attach to surfaces, swim through liquids and escape predators. There is an article based on research by ...


14

Unfortunately, we do see examples of bacteria and viruses evolving vaccine resistance. For instance, vaccine resistant strains of polio and pertussis have recently been identified. Yet these seem like the exception rather than the rule. One thing that makes it harder for pathogens to evolve resistance is that vaccines usually generate antibodies to ...


14

It's a fascinating topic! While most of the bacteria known to colonize babies comes from the vaginal tract during birth and then later, through breastfeeding, although there is evidence to suggest that microbial colonization may begin before birth. Regarding what these bacteria are, our microbiomes are composed of probably hundreds of species of bacteria ...


14

There are giant viruses that some people think could be degenerate bacteria. https://en.wikipedia.org/wiki/Mimivirus Mimivirus shows many characteristics which place it at the boundary between living and non-living. It is as large as several bacterial species, such as Rickettsia conorii and Tropheryma whipplei, possesses a genomic size comparable ...


13

Edit: Matters Arising In this Nature News article, Scientists bust myth that our bodies have more bacteria than human cells, and in the bioRxiv pre-print article, Revised estimates for the number of human and bacteria cells in the body, a new estimate of the ratio of microbial cells on the human body to human cells that make up the body has been revised ...


12

Microwave ovens can indeed kill bacteria in food by heating them to high temperatures. For example, this article found that microwave heating could kill all of the Salmonella bacteria in a chicken thigh sample: The effect of microwave heating on Salmonella Enteritidis inoculated on fresh chicken was investigated using a microwave oven (800 w) to ...


12

I am not sure what you read as you have not supplied any references, but humans are not 90% bacterial cells. (OP subsequently provided; see Edit 2) Humans are 100% human cells, however for every one human cell, approximately 10 single celled organisms (Bacteria or Fungi) live in (colloquially) or on the human body. This is referred to as the microbiome. You ...


12

According to a number of citations listed on Kenyon College's MicrobeWiki, rain can contain microorganisms via a process called "bioprecipitation." Essentially, microorganisms, dust and other small particles get swept up into the atmosphere, and cold temperatures cause atmospheric water vapor to freeze around the organism/particle. Once the ice-covered ...


12

The authors propose that this is a distinct species based on a number of physiological and genetic tests. To quote the summary of your linked paper In summary, the phylogenetic and genetic distinctiveness and differential phenotypic properties were sufficient to categorize these three ISS strains as members of a species distinct from other recognized ...


11

You might need to demote your single-celled 'lords' to 'squires'. They're not essential to an individual's life. You wouldn't die (dispensing with the "how" right off the bat.) You'd be just fine if no bacteria reentered your body. Your fecal output would be greater; you would derive somewhat less nutrition from your food, you would need to take vitamin K, ...


10

Antibiotic resistances in bacteria is commonly encoded by extrachromosomal DNA, the plasmids. These are circular pieces of DNA, which are much smaller than the hosts genome and which replicate independently from it. See the image from the Wikipedia: These plasmids can be transfered between different bacterial cells, which then also get resistant. Plasmids ...


10

Yes, this is possible and is researched as an alternative to antibiotics. It has been used experimentally before antibiotics became widely available. Research was abandoned when antibiotics became widely available. See for example here and here for reports on this. Today bacteriophages are researched for the treatment of bacteria which have a lot of ...


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