13C NMR studies of the binding of soybean trypsin inhibitor to trypsin.

NMR studies of the complex between trypsin and soybean trypsin inhibitor with 1-¹³C-arginine and modified inhibitor with 1-¹³C-lysine show that these complexes involve almost exclusively non-covalent binding of the inhibitor to the enzyme for trypsin/¹³C-Lys-inhibitor at pH 6.5 and 8.1 and for trypsin/¹³C-Arg-inhibitor at pH 5.0. At pH 7.1 for trypsin/¹³C-Arg-inhibitor both non-covalent and acyl enzyme forms are observed. Under no conditions did we observe evidence for a tetrahedral adduct between enzyme and inhibitor.     

Differential Renal Function Study—An Aid in Preoperative Evaluation of Hypertensive Patients

Non-occlusive ureteral catheters were placed bilaterally in the renal pelves of 30 patients known to have hypertension. Samples of urine were collected under conditions of normal hydration, of urea-PAH-saline diuresis and, in some cases, mannitol diuresis. The samples were analyzed for indications of impaired flow of blood to the kidneys. Aortograms were obtained in all cases.This placement of non-occlusive catheters up into the renal pelves was felt to have caused only minimal disturbance of renal function, and was not accompanied by ureteral edema with the concomitant complications caused by occlusive catheters. Under conditions of normal hydration, leakage was insignificant.Of the 20 patients in whom urea-PAH-saline infusion revealed an ischemic pattern, 19 had an ischemic pattern under conditions of normal hydration. Since in the one exception an aortographic examination did not show a surgically reparable renal lesion, it may be inferred that the use of urea-PAH-saline diuresis is not essential in the preoperative evaluation of hypertensive renal disease.Correlation of the results of differential renal function studies and aortographic findings was possible in 19 of the 30 patients. Lack of correlation in the remaining 11 patients emphasized the importance of obtaining both types of study.Aortographic examination combined with differential renal function studies, using small ureteral catheters under conditions of normal hydration, should give the urologist a practical and yet accurate method of determining differential renal blood flow. If desired, further verification could be obtained by administering contrast medium and performing serial measurements of urine density.     

Depth and habitat distributions of three species of rockfish (Sebastes) in British Columbia: observations from the submersible PISCES IV

Synopsis I describe a technique to quantify spatial distribution patterns of deep reef-fishes, and apply this technique to inshore rockfish (Sebastes) communities in the Strait of Georgia, British Columbia, Canada. Observations were made along vertical transects between 21–140 m using the submersible PISCES IV. A total of 31 transects were completed at 14 sites during 16 submersible dives. S. elongatus, S. maliger and S. ruberrimus were the dominant rockfish species that were observed. S. elongatus and S. ruberrimus had similar depth distributions, but tended to segregate by habitat type. S. elongatus was most abundant on mud and cobble substrates that interspersed rocky areas. S. maliger and S. ruberrimus were both abundant in complex rock habitats, but tended to segregate by depth. For all three species there was an increase in size with depth. Hence, habitat type and depth were important influences on distribution patterns of this species group.     

Modes of action of intracellular dextranase and three oligoglucanases from Pseudomonas UQM733

The action patterns have been studied of a purified, intracellular dextranase and three intracellular alpha-D-glucosidases from Pseudomonas UQM733 on pure isomalto-oligosaccharides. The glucosidases have optimal activity on isomaltotetraose and are therefore classified as oligoglucanases. They have been used to determine the structure of two branched isomalto-oligosaccharides obtained by enzymic degradation of dextran.