Chinese hamster ovary cell production of recombinant tissue‐type plasminogen activator (t‐PA) was increased by amplification of cotransfected dihydrofolate reeducates cDNA using stepwise adaptation to increasing methotrexate (MTX) concentrations. The highest producing clones were isolated at 5 μM MTX and yielded 26,000 U/106 cells/day t‐PA (43 μg/106 cells/day). Above 25 μM MTX, cell specific t‐PA production rates became increasingly variable and the cDNA copynumbers decreased. No apparent correlation between the cell specific t‐PA production rate and the growth rate was observed upon sub cloning of the amplified cells. When MTX selection was removed, the t‐PA production rate decreased up to tenfold within 40 days; this was accompanied by an up to 60% drop in cDNA copynumber. Subclones isolated after 108 days of culture in the absence of MTX were, on average, sixfold more stable than their parental cells. In culture without MTX, the maximum stable t‐PA production rate obtained (over 250 days) was 7000 ± 750 U/106cells/day (∼12 μg/106 cells/day), approximately threefold lower than the maximum unstable levels of production reached under selective pressure. Taken together, these results define a wide range of the highest t‐PA expression rates obtained under MTX selection, for which stable expression without selection has not been reported
Answer:
The answers that apply;
Researchers found cosmic microwave background radiation, which is a heat imprint left over from the big bang.
A redshift of light emitted by stars and galaxies indicates the universe is expanding
A primordial form of helium gas was found by the Endeavor space shuttle
Big Bang theory is a theory that endeavors to explain the origin of the universe. It stipulates that the universe exploded from a singularity and continues to expand today
Explanation:
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Answer:
Soil condition directly affects crop growth.
Explanation:
Soil condition affects the crop growth directly. If a soil is in fertile condition then the growth of crop which is growing in such soil will be good but if the soil is infertile then the crop will not grow to its fullest. A fertile soil is the one which has optimum condition for growth of a crop like suitable pH, moisture retention capacity, good amount of nutrients & minerals like nitrogen, phosphorus, sodium, potassium, magnesium etc. If a soil is rich in all these constituents then the crop which is growing in this soil will be healthy. But, if a soil is infertile then the crop which is growing on that soil will be under stress and will not be able to grow completely.
Answer:
D) H in glucose and water; O in O2
Explanation:
In green photosynthesizing plants, photolysis occurs during the light-dependent phase. Photolysis is the splitting of the water molecule in the presence of sunlight. The oxygen atom of water molecules forms oxygen gas that is released as a by-product of photosynthesis. Photolysis also releases electrons and protons from water molecules that finally reduce the NADP into NADPH.
The light-independent phase of photosynthesis fixes reduces CO2 into glucose. NADPH serves as reducing power during the light-independent chemical reactions and therefore, the H atoms from water molecules are incorporated into glucose and water molecules formed during light-independent reactions of photosynthesis.
The third trimester begins at B) seven months.
The first trimester: 1-3
The second trimester: 4-6
The third trimester: 7-9.
