Synthesis of poly(A) containing RNA induced by ecdysterone in fat body cells of Calliphora vicina

The insect-hormone ecdysterone causes a de novo synthesis of RNA in the fat body cells of blowfly larvae. Hybridization of the RNA induced by the hormone with ³H-Poly(U) demonstrates that it contains poly(A) sequences and therefore is probably informational. DNA-RNA-hybridization experiments further show that qualitatively new mRNA species are synthesized under the influence of ecdysterone. The inducibility of RNA synthesis is strongly correlated to specific developmental stages.     

A new dynamometer measuring concentric and eccentric muscle strength in accelerated, decelerated, or isokinetic movements. Validity and reproducibility

A new computerized dynamometer (the SPARK System) is described. The system can measure concentric and eccentric muscle strength (torque) during linear or nonlinear acceleration or deceleration, isokinetic movements up to 400 degrees.s-1, and isometric torque. Studies were performed to assess: I. validity and reproducibility of torque measurements; II. control of lever arm position; III. control of different velocity patterns; IV. control of velocity during subject testing; and, V. intra-individual reproducibility. No significant difference was found between torque values computed by the system and known torque values (p greater than 0.05). No difference was present between programmed and external measurement of the lever arm position. Accelerating, decelerating and isokinetic velocity patterns were highly reproducible, with differences in elapsed time among 10 trials being never greater than 0.001 s. Velocity during concentric and eccentric isokinetic quadriceps contractions at 30 degrees.s-1, 120 degrees.s-1 and 270 degrees.s-1 never varied by more than 3 degrees.s-1 among subjects (N = 21). Over three days of testing, the overall error for concentric and eccentric quadriceps contraction peak torque values for 5 angular velocities between 30 degrees.s-1 and 270 degrees.s-1 ranged from 5.8% to 9.0% and 5.8% to 9.6% respectively (N = 25). The results indicate that the SPARK System provides valid and reproducible torque measurements and strict control of velocity. In addition, the intra-individual error is in accordance with those reported for other similar devices.     

Purification of prophenoloxidase in the haemolymph of Calliphora vicina (R. & D.).

An improved method for the purification of prophenoloxidase is described. The proenzyme was purified 400 fold in homogenous form. The purity was tested by disc-electrophoresis and the molecular weight was found to be 87 000 in comparison to the mobility of marker enzymes, which were run simultaneously in SDS-gel electrophoresis. The proenzyme was denatured at 80 degrees C and maximum conversion into active state was found between 40 and 50 degrees C.