Characterization of developmentally regulated epitopes of Schistosoma mansoni egg glycoprotein antigens

The chemical and antigenic composition of a major group of concanavalin A-binding glycoprotein antigens of Schistosoma mansoni eggs was examined by the use of monoclonal antibodies. The individual glycoproteins of this group each displayed a very wide range of apparent m.w. and had isoelectric points of less than 5 when analyzed by two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis. These glycoproteins could be chemically labeled with 125Iodine by two different methods and biosynthetically labeled with 35S-methionine during in vitro synthesis by isolated eggs. By using five monoclonal antibodies, the individual egg glycoproteins were shown to share several antigenic determinants when analyzed by radioimmunoprecipitation and solid-phase binding assays. These epitopes were present in a high level, and the degree of expression appeared to be developmentally regulated. In addition, Schistosoma haematobium and Schistosoma japonicum eggs contained antigenically related glycoprotein antigens. Preliminary evidence suggests that the epitopes involve carbohydrate moieties.     

Seaward migrating Atlantic salmon smolts with low levels of gill Na+, K+ -ATPase activity; is sea entry delayed?

Two groups of migrating wild Atlantic salmon (Salmo salar) smolts caught within a 1 week interval in the River Alta, northern Norway, were tagged with acoustic transmitters and measured for gill Na⁺, K⁺ -ATPase activity in order to compare their smolt status with timing of sea entry. The first group of smolts had low levels of gill Na⁺, K⁺ -ATPase activity and resided in the lower part of the river twice as long as the second group that had high levels of gill Na⁺, K⁺ -ATPase activity. This indicates that early migrating smolts may not be completely physiologically adapted for salt water and delay their sea entry, thereby also synchronizing their seaward migration with the later migrating smolts.     

The fishing conservation and management act of 1976: Economic issues associated with foreign fishing fees and foreign allocations

Abstract

In April 1976 President Ford signed Public Law 94–265, the Fishery Conservation and Management Act of 1976. As this legislation comes of age, a far‐reaching and new approach to the management of our nation's fishery resources will be set into motion. Some of the most significant provisions of the Act are the restriction on the amount of foreign fishing, the charging of fees for foreign fishing privileges, and an enormous expansion of the area over which the United States exercises fisheries management control. This article briefly explains why the Act came into existence and what its key provisions are. It outlines the proposed foreign fee system for FY1977 and discusses the important economic impacts upon the United States from foreign fishing fees and restricted amounts of foreign fishing. It then examines possible policy questions and the important economic information necessary to assess them.     

Electrophysiological and contractile responses of canine atrial tissue to adrenocorticotropin

The direct extra-adrenal actions of adrenocorticotropin 1-39 (ACTH) on electrical (E) and mechanical (M) characteristics of canine atrial tissues (AT) were investigated in in vitro experiments. One hundred twenty-five mU/ml of ACTH 1-39 significantly augmented the catecholamine induced positive inotropism as seen by shortening the time to peak tension (10.6%, p = 0.01) and increasing peak isometric tension (3.5 times, p = 0.001). Effects on the M responses were inhibited by propranolol (10(-6) M) (P). ACTH did not significantly modify action potential E or M parameters during cholinergic receptor antagonism or alpha-adrenergic receptor antagonism. Existence of a specific ACTH receptor was demonstrated using 125I radioiodinated ACTH 1-24. Significant binding of 125I-ACTH to AT was observed. Intracellular C-AMP levels were also measured in AT using radioimmunoassay. Tissues were exposed to 125mU/ml ACTH 1-39 plus combinations of norepinephrine (10(-6) M) (NE) and P. ACTH alone did not elevate intracellular C-AMP levels. NE increased C-AMP levels were not further increased by ACTH. Exposure to antagonist returned elevated C-AMP levels to control values. In conclusion (1) ACTH augments the NE induced M positive inotropism of the beta adrenergic receptor system. (2) ACTH specifically binds to AT and (3) ACTH does not utilize the C-AMP second messenger system.