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8

To summarize from Hanahan's paper (see below for reference), he carried out a systematic review of conditions necessary to improve transfection efficiency. Among the conditions tested were the presence of various cations (Ca2+, Cs+, Mn2+, K+, Mg2+), DMSO, and growth temperatures (and a few other conditions not so commonly used these days). He worked with a ...


6

Clostridium botulinum toxin is present ubiquitously in soil. As such it is more than plausible that hay bails, which come into contact with soil can and I should expect almost probably will be infected with these bacteria. However it is not the mere presence of the bacteria itself which causes poisoning, it is the toxins they produce when the appropriate ...


6

(Super Optimal broth with Catabolite Repression) SOC media has glucose where as Luria Broth (LB) doesn't. SOB also has a more delicate salt balance. Naturally the glucose will help the cells recover and grow faster after the heat shock. Your transformation efficiency should improve since less cells will die. On the other hand, the reason why SOC media ...


6

C. elegans needs cholesterol, but can't make it. Since bacteria don't make cholesterol either, the food bacteria aren't a source. As explained in the linked paper, lack of cholesterol affects normal development.


4

As an addendum to Spinorial's answer, and after some research, the Center for Food Security and Public Health specifically lists hay / grass / decaying vegetable matter as a potential source for C. botulinum growth in their (very informative) Botulism PDF. All species of Clostridium can produce spores, dormant forms of the organism that are ...


3

Not sure that I have ever come across trace metals in recipes (I assume that you aren't referring to the Ca/Mg salts component of M9), but it is certainly the case that many K12 strains (e.g. C600, DH5α) require thiamine because they are thi mutants. This doesn't apply to BL21 since it is from a different lineage (it is a B strain). In a lab where ...


3

See here. Bacto is a brand which used to be marketed by Difco. It is a casein (milk protein) hydrolysate.


3

Not well, they need dextrose. Use YBT: 20 g Casein Peptone Tpe-M 10 g Yeast Extract 20 g Dextrose 17 g Agar q.s. to 975 mls in di-water. pH to 6.2 w 5M NaOH q.s. to 1L with di-water. Autoclave for 45 min at 121C Aseptically dispense in Petri dishes. Store at 4C for up to 12 weeks. If you want to grow Co-culture do so in LB supplemented with 20g/L ...


2

I've published a paper comparing different measures of specificity, if that is of any help. But if you plan to have, e.g., measures of performance on carbon sources, pH, and temperature, then you'll have three measures of specificity (i.e. one for each). Also, worth to have a look at Graham Bell's inconsistency and responsiveness, as used by Venail et al. ...


2

I have used terrific broth to grow up transformed E. coli so they grow faster. Often people will conduct a transformation, screen the cells, and grow them up in broth for plasmid extraction. This growth would be for 12-16 hours. Instead a person could use terrific broth to grow up the cells and it would take may 6-8 hours for adequate cell density for ...



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