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77

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 ...


34

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 ...


26

Vibrio cholerae is known to have two circular chromosomes. Bacteria cell division is a lot simpler and efficient as compared to eukaryotic cell division, partly due in part to the nature of their chromosomes. They don't have to undergo mitosis -- condensation of chromosomes, segregation, spindle fibre formation, attachment et al aren't involved in bacterial ...


20

Bacteria usually gain resistance mechanisms through horizontal gene transfer (such as conjugation and phage infection). The four main mechanisms in which bacteria elude antibiotics are: Drug Inactivation: For example, E. coli can produce beta-lactamase that inactivate many lactam based antibiotics such as penicillin. Alteration of Target Site: Mutations in ...


19

No There are several reasons why this might not be true, as Alexander has discussed. An antibiotic often has a molecular target that isn't present in all bacteria, it's extremely hard to get antibiotics to certain parts of your body, and some bacteria will be defended against a antibiotic attack by biofilms, resistance mechanisms, and sheer statistical ...


19

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 ...


18

To expand a little bit the other answer, I would also add that bacteria can have other (usually circular) DNA segments aside from their main chromosome. These are called plasmids and are double stranded molecules of DNA that can replicate autonomously. Plasmids often carry genes that allow an organism to survive in certain conditions, for instance they ...


18

Bacteria have a mesh-like structure surrounding their plasma membrane called a cell wall. The cell wall is made up of peptidoglycan polymers that form a rigid crystalline structure that helps protect the osmotic pressure of the bacterial cytoplasm. Penicillin and other β-lactams work by inhibiting the final step of peptidoglycan synthesis, which ...


16

Just a quick answer: No, there is no way to kill all bacteria in your body once they are there. The only way to keep a person sterile is to prevent any bacteria entering the guts during and all time after the birth. Look for gnotobiology and gnotobionts to learn more about these organisms (including humans). Here are some reasons why: Most antibiotics ...


15

Simply put, old habits die hard; physicians and other medical personnel have grown up with the old species designations so will continue to use them. This is somewhat the reverse of the case with E. coli, where 80-90% of the genome is variable across strains. Lin-Hui gives a brief history, where strains identified early were given specific names within ...


15

Mitochondria are very similar to bacteria and are thought to have originated from bacteria. This points you to the answer: bacteria produce ATPs the same way mitochondria do, with the oxidation machinery place in their plasma membrane (analogous to the mitochondrial membrane).


15

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

Growth can be quite slow for some species under certain conditions when the concentration of cells is too low. Log-phase growth is powerful, and so one would like to keep cells in this state for the experiment at hand. Different genes are expressed then compared to a stationary phase. In addition, you'd like your culture to out-compete a contaminant if ...


14

An antibacterial is any compound that will kill or at least slow down the growth of strictly bacteria, a domain of prokaryotes. An antibiotic is often used synonymously, but denotes a compound that kills or slows down the growth of any cellular pathogen, prokaryotic or eukaryotic. So, certain antibiotics can kill bacteria, fungi and parasites but ...


14

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 ...


14

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 ...


12

Also, what research is being conducted to combat bacteria resistant to antibiotics? You've gotten some decent answers for how antibiotic resistance arises, so I thought I'd touch on this a bit. There's three major thrusts to anti-resistance research: Finding new targets and mechanisms. Essentially, creating new antibiotics that are subtly different ...


12

I think the current answer to this for bacterial infections is quorum sensing. Quorum sensing is a signalling pathway in bacteria which senses a molecule that the bacteria themselves secrete. When the concentration of the quorum signal reaches a certain level, the bacteria interpret this as their population density reaching some threshhold. Bacteria are ...


12

The hoatzin has a digestive system that makes use of bacterial fermentation. Many other birds also consume grass, e.g. ostriches, ducks and geese. There's also a large body of literature on how birds can digest cellulose.


12

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 ...


11

I think that cells get damaged at -20°C not because they are stored for a long period of time, but because they undergo cycles of thawing and freezing (the ice crystals that form damage them). I never keep cells at -20°C. I store them at -80°C in 50% glycerol. The idea behind the glycerol is that it serves as cryoprotecor. It forms hydrogen bonds with the ...


11

Most of the initial colonisation is said to be coincidental ('happenstance' as the textbook puts it!) exposure. It's then fairly predictable depending on: type of delivery (as Larry commented); feeding; and receipt of antibiotics. In terms of feeding, there are differences in flora between babies fed human milk and those that are given cow's milk. ...


11

There are a number of ways to address antibiotic resistance in infectious bacteria. What one gets used depends on exactly what organism we're talking about. But below is a short list of some ways: Changing the antibiotic being used. Not all antibiotics have the same molecular target within a bacterial cell. Some interfere with the formation of the cell ...


11

The lead question you have answered yourself: bacteria become resistant because of the selection pressure caused by the antibiotic's effective suppression of the original non-resistant bacteria. Those variants which resist the suppression are selected for as a natural consequence. How do resistant bacteria process antibiotics? It depends on the details of ...


11

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 ...


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

The goal of hand washing is to remove surface debris, including foreign pathogens. Most things that most people encounter on a daily basis dissolve more easily in hot water than in cold water. Thus, hot water around 100° F is used to facilitate this debris removal process, although the ideal culture temperature for E coli and a raft of related bacteria is ...


10

This is a matter of pragmatism in the culture process. Taking 100 colonies instead of 1 increases the inoculation volume by a factor of 100, which then saves you perhaps 2 hours of bacterial growth time before your culture reaches the OD you want. However, mutations and loss of plasmid in culture, while unlikely, are possible, especially if the bacteria ...


10

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 ...



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