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
The muscle that inserts on the acromion and scapular spine is the Trapezius.
The trapezius muscle inserts into the scapular spine acromion and posterior superior lateral clavicle. Contraction of its various parts thus allows the scapula to be lifted, suspended, stabilized, and rotated. inserted. The deltoid muscle inserts into the acromion process, the main muscle that raises and extends the arm.
In humans, the acromion process can be flat curved hooked, or convex depending on the shape. The intrinsic muscles of the scapula include the rotator cuff teres major subscapularis teres minor and infraspinatus. These muscles attach to the surface of the scapula and assist in the abduction and external and internal rotation of the glenohumeral joint.
Learn more about The acromion here:-brainly.com/question/28192526
#SPJ4
Answer: synthesize RNA by following a strand of DNA. RNA polymerase is an enzyme that is responsible for copying a DNA sequence into RNA sequence, during the process of transcription
Explanation:
Answer:
A
Explanation:
The water builds up in the cell, so B and D wouldn't make sense, and solutes don't enter the cell
