New Medication Against Heart Attack

Monique

Spiderweb fiber is one of the strongest compounds known to exist in nature. What you can do with that? Just imagine :)

Why goats are a better source.. well.. [:D] how much web does a spider make in a day and how much milk does a goat make a day.. quantities ar the issue here.

rockind78

In a microbiology or molecular biology lab for instance, when the scientiest wants to maintain the presence of foreign DNA in a system, they use antibiotic resistance genes, growing the cells in the presence of the antibiotic. So in otherwords, if you wanted the continuted expression of your desired protein, and it it was sizably feasible to fit the gene encoding it into a plasmid that was readily transformed into a cell at a high efficiency, than what would stop someone from cloning the gene into a plasmid containing an antibiotic resistance gene and grwoing your cells in approporiate media with a sufficient concentration of the relative antibotic?

In utilizing this type of methodology, how would the gene of interest be "lost"?

zoobyshoe

How far have they gotten with this? Is there an actual bullet proof vest made from spider webs in existence? Or have they simply demonstrated the feasabilities on paper?
Yes, I can see now that if you can spin it from a liquid under controled conditions it would be easier than collecting by hand. It's not the same thing as with the silk moth.

Monique

Antibody resistance would be generated in the other cells. Also, you'd have to use a lot of antibiotics since it is continually used up, I guess it is expensive?

In my lab too, we grow all our cell lines (not transfected though) without any antibiotics.

Monique

Correct me if I am wrong, but I am pretty sure that bullet proof vests made from spiderweb fiber are already in use today. Another advantage is that the material is very light AND strong.

zoobyshoe

Amazing. I would imagine they could make full body garments out of it, including full face and head protection, given that it is light.

Do you know if it's fireproof or merely fire resistant? It melts, maybe, in a hot fire?

rockind78

I'm not sure I am following you here. Let me give you an example. the laboratory goal for this semester of my molcular biology class is to clone a fragment of the fur gene for chinese hamsters. Once the PCR product has been cleaned up, digested, and ligated into a specific plasmid, the gene can then be replicated. This is accomplished through the fact that the plasmid we are using codes for ampicillin resistance and the lac genes . Additionally, the MCS (multiple cloning site) for this plasmid is located in the middle of the lac Z gene. After transformations, the cells are plated out on ampicillin fortified LB agar that is treated with IPTG and XGal. These are both lactose analogs. One cannot be metabolized but is rather contiuously recycled as an inducer for the lac genes. The other turns blue when it is cleaved. Once the cells grow up, if they grow up, we know just from looking whether or not

1) the plasmid was taken up, as evidenced by growth on the medium
2) whether or not the gene was properly ligated in by way of a color change of the cells.

My point behind all this, is that although it would be expensive (that I will grant you), how would the antibiotic resistance be conferred to the the cells not carrying the plasmid, especially in genetically modified cloning strains?

The selective pressure of the antibiotics I would think keeps the plasmid, and thus the gene, in the cells as long as the antibiotic concentrations were up to par and the cultures were kept fresh.

Monique

Ian would be able to give a better explanation, but bacteria are able to readily take up DNA from their environment. This is what causes many pathogenic bacteria to become resistent to all kinds of antibiotics. I read an article in the paper today where, I believe, in France a highly resistant bacteria is on the rise..

Since the bacteria who initially weren't resistant also don't have the insert, they would have a significant growth advantage after aquiring the antibody resistance gene and take over the culture since they grow faster without the stress of being a protein factory.

iansmith

If the antibotics is used from the start of the batch culture and kept at the concentration requires bacteria not carrying the plasmid will die and won't have an advantge. What could happen is random resistance because the batch is use over and over and the selective pressure is great. Bacteria not carrying the plasmid migth and resistant to the antibitotics.

As far as for uptake free DNA, some strain of bacteria are not good at it. Most E. coli used are recombianse negative in order to decrease recombiantion and circular DNA is harder to uptake than linear DNA.

There is a system that could be used without the need for antibitotics. Some plasmid are retained not matter what happen. These plasmid carry a poison and an antidote. The antidote is unstable when free and the poison is stable. If the plasmid is not segregated then the antidote is degraded and the poison kills the bacteria.

Monique

Have you ever seen those incubators? They are HUGE. Six meters (18 foot) high if I remember the picture correctly. It mustn't be easy to keep those contamination free.

iansmith

These are more or less closed system. If you have a good sanitaziton plan it can be kept contamination free.

Also you can also use media that are specific for certain species. these are called selective media and contain salt concentrion or coumpound that inhibit the grow of certain groups and species.