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5

The minimum requirement for E. coli and other bacteria to grow and survive is called minimal medium. It's even defined at Merriam-Webster: a medium that contains only inorganic salts, a simple carbon source (as carbon dioxide or glucose), and water Water and glucose are pretty easy, but the source of salts may often change; regardless, you really need ...


4

Some things to consider. If you spinning too fast and too long, ti's going to pack the pellet more. You can spin longer at a slower speed and you will notice your pellet is not as packed. I always do 2000 rpm, 20 minutes, 4C if I'm doing a midi or maxi sized prep and harvesting bacteria in 50ml conical's. If I'm doing a miniprep I will take the 1.5 micro ...


4

NAD+ is important in this step, since it is co-factor for the glyceraldehyde-3-phosphate dehydrogenase (G3PDH), which acts as a acceptor for the hydrogen atom from the C1 (see below). If you look at the reaction, the aldehyde from the C1 is oxidized to a carboxylic acid which in a second step is turned into a phosphoester. To do so, a cysteine from the ...


4

Let me first clarify the difference between anaerobic respiration and fermentation. Literally respiration refers to breathing, but its definition has been extended to include cellular metabolism that leads to ATP generation. Fermentation, as you said depends on substrate level phosphorylation. Anaerobic respiration on the other hand just means ATP ...


4

This question got me thinking about what are the metabolic enzymes that take oxygen up in E coli. I searched the metacyc database for reactions that consume molecular oxygen and there are only 3 that take in oxygen and one that produces oxygen. All three consumers of oxygen in E coli are the oxidation of ubiquinone by at two sites in cytochrome bcl or by ...


3

The plasma membrane is quite permeable to oxygen and thus oxygen enters the cell simply by diffusion. Reactive oxygen species can be reduced enzymatically in aerobic organisms. Obligate anaerobes lack or don't produce sufficient quantities of these enzymes. An organism that doesn't use oxygen for metabolism but is also not relatively harmed by it can be ...


2

There are three variables being shown here: The amount of time samples were stored in the freezer to allow $^{32}$P decay (x-axis), The length of time samples were allowed to grow in a nonradioactive environment before being frozen (points with different symbols), and The rate of $\beta$-galactosidase production when cells were thawed and grown in the ...


2

The traditional blue/white screening is set up so that blue colonies are considered positive for the insert, and white colonies are negative. The gene responsible is the lacZ gene, or beta-galactosidase. This enzyme converts a synthetic substrate, X-gal, into an insoluble blue compound. The pCR2.1 TOPO plasmid is a blue/white selection plasmid in which ...


2

I found that E. coli exposed to predators such as amoeba changes completely from normal form to filaments (on agar) that look wound up like spaghetti but are not only longer but significantly wider. In this form the predator can't attack E. coli and it lives among the amoeba for extended periods. It does not look like a simple point mutation to me, which ...


2

Yes, but no. In other words, this quote is not probably not true in the ways you'd think. Bacteria can survive on practically nothing for long periods of time, but whether you call that life is subjective. Nitrogen is necessary for all the co-enzymes and proteins to sustain life. In order to get energy, if E coli. needs to metabolize nitrogen to waste at ...


1

I did try another transformation: again with our electrocompetent cells Cells form other lab chemically competent cells I made The good thing is that on chemically competent cells there is no weir colonies, however efficiency of transformation was very low, but still, I think it is ok - will confirm it in next day if I really got the right insert. On ...


1

That is a variable that you have the pleasure defining yourself. Just know that using a buffer will introduce other atoms that could affect the "living things". Conversely, if you don't use a buffer, it is likely that the pH of your "living things" will be easily altered by the metabolism of your living things (IMHO, this is worse). I don't know the details ...


1

According to this data sheet, the genotype of the strain RosettaTM(DE3)pLysS is F- ompT hsdS (r- m-) gal dcm (DE3) pLysSRARE (CamR). This strain carries certain tRNA genes on the same plasmid as the LysS gene, and these tRNAs boost expression from genes containing rare (in E. coli) codons. The plasmid encodes chloramphenicol resistance (CamR). If you have ...


1

Absolutely, Positive Selection You are looking for the bacteria which have the gene (probably a plasmid) you (or someone else for you) put into the bacteria. That gene lets them live in the presence of kanamycin, and any bacteria that don't have it, or that try to get rid of it, will die. Thus you can select for the bacteria you want by killing everything ...



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