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The activity of phe-hydroxylase was determined in liver needle biopsy material from patients with elevated phe levels. The reaction mixture for the enzyme assay was: phosphate buffer 150mM, phe 0.1mM, phe 14C 0.2μCi, dithiothreitol 2mM, biopterin 0.025mM. The extract was preincubated with lysolecithin (1mM) for 10min, the reaction stopped by boiling. Phe and tyr were separated by TLC. 14-C-activity was determined by direct scanning and counted in a liquid scintillation counter. So far we have observed 4 types of enzyme activity: 1) Control liver samples of non-metabolic disorders transformed 100μmoles/g−1 protein/60min−1 from phe to tyr. 2) Socalled hyperphe-aemia (phe levels around 10 mg%) had 10-20% normal activity. 3) A third group had 1-6%. 2 pairs of siblings also showed this residual activity. One sib in each family had not been treated (late discovered) and was mentally retarded, the other developed normally under treatment. 4) “Classical” PKU had no detectible hydroxylase activity. -This study intends to differentiate PKU from other hyperphe-aemias which perhaps may remain untreated.

Fenbutatin-oxide, Vendex, was applied as a 50% wettable powder or 4L liquid formulation alone and in combination with either medium (FC-435) or light (FC-412) petroleum oils on citrus to control the citrus rust mite, Phyllocoptruta oleivora (Ashmead). Lower rates of the miticide in combination with either oil at 1% resulted in a significant reduction in residual activity in controlling rust mite versus the miticide applied alone.

Abamectin was applied to tomato in the field and treated foliage was bioassayed in the laboratory 0, 1, 3, 5 and 7 days after treatment for affects on Liriomyza trifolii (Burgess). Surface residues on leaflets increased mortality of adults only when bioassayed on the day of treatment. Oviposition and larval abundance were reduced even when leaflets were bioassayed 7 days after treatment. Leaf puncturing (stippling) by females was reduced for 3 days after treatment.

The spectrophotometric assay of serum ADH of the quail-chicken hybrid shows, after thermal denaturation carried out at 50 degrees C, a greater residual activity that that of either parental serum; such increased resistance to heat reflects a greater stability of the hybrid molecule.

IN the course of investigations into detergency using radioactive isotopes, some interesting observations have been made. The chopped fibre technique1 was used, and the cotton fibre was soiled as described previously2, but with a proportion of the stearic acid replaced by stearic acid-1-14C. The rate of removal of stearic acid from the fibre after washing with different detergent solutions for various times was measured by the residual activity of the fibre compared with the initial activity of the unwashed fibre. The fibre was made into smooth pads and activities were determined by an end-window counter.

The uptake, translocation, and metabolism by O. pes-capl'ae plants of carboxyl-and methyl-labelled [14C]-2,4-dichlorophenoxyacetic acid (2,4-D) were studied by chromatographic, radioautographic, and scintillation-counting tech-niques. In young O. pes-caprae plants some translocation of 14C out of the treated leaves occurred while in older plants it was severely restricted. Qualitative and quantitative chromatography of the acidic fructions of methanolic extracts soluble in ethel' or ethyl acetate or both revealed the presence of at least 12 radioactive compounds, often within 1 day from treatment. The bulk of the activity (90-95%), was present in a spot chromatographically identical with 2,4.D regardless of the region of the plant or the position of 14C in the molecule. Evidence was obtained that about half of the "presumed" uptake was not accounted for even after 14002 evolution, leakage from roots, and residual activity in extracted material are taken into account. The observed instability of the various radioactive products upon .rechromatography underlines the caution that must be exercised in interpreting the physiological significance of interconversions. It is concluded that restricted trans-location and metabolic attack of the 2,4.D molecule, with the formation of unstable intermediates, some of which may be volatile, are contributing factors in the high resistance of O. pes�caprae to the herbicidal action of 2,4-D.

Porcelain ware produced by Coors has been found to be exhibit residual activity that may be used as a suitable standard.

Photoreactive compounds are important tools in life sciences that allow precisely timed covalent crosslinking of ligands and targets. Using a novel large-scale technique we have synthesized azidoblebbistatin, which is a new derivative of blebbistatin, the most widely used myosin inhibitor. Without UV irradiation azidoblebbistatin exhibits identical inhibitory properties to those of blebbistatin. Using UV irradiation azidoblebbistatin can be covalently crosslinked to myosin, which greatly enhances its in vitro and in vivo effectiveness. Photocrosslinking also eliminates limitations associated with the relatively low myosin affinity and water solubility of blebbistatin. Irradiating light used for photocrosslinking is not toxic for cells and tissues, which confers a great advantage in in vivo tests. As the crosslink results in an irreversible association of the inhibitor to myosin and the irradiation eliminates the residual activity of unbound inhibitor molecules, azidoblebbistatin has a great potential to become a highly effective tool in both structural studies of actomyosin contractility and the investigation of cellular and physiological functions of myosin II.