Sulphamerazine toxicity in cut-throat trout broodfish Salmo clarki (Richardson)

Treatment of cut-throat trout broodfish Salmo clarki (Richardson) with Sulphamerazine at 220 mg/kg (10 g/100 1b) of fish/day for 14 days resulted in severe kidney histopathology and increased mortality among males. Experimental data presented showed that cut-throat trout broodfish were extremely sensitive to Sulphamerazine toxicity. Hydropic degeneration of renal tubule epithelium and haemorrhage into tubule lumens were observed in kidneys of both male and female trout, but was more severe in the former. Death, which occurred only in males, was correlated with spawning stress and impaired renal function.     

Ultrastructure of type-I salivary-gland acini in four species of ticks and the influence of hydration states on the type-I acini ofAmblyomma americanum

We describe the ultrastructure of type-I salivary-gland acini in two argasid and two ixodid species. The basic cell types in the agranular or type-I acini, and their associations, are very similar in argasids and ixodids; therefore, we propose an anatomical nomenclature for cells in the type-I acinus based on the adult ixodidsAmblyomma americanum andDermacentor variabilis, and the argasid adultArgas (Persicargas) arboreus and on nymphalOrnithodoros moubata. Four cell types were present in all specimens: one central lamellate cell, a variable number of peripheral lamellate cells, a variable number of peritubular cells depending on the species, and one circumlumenal cell. The lamellate cells had infolded basal plasma membranes that presented an amplified surface area to the hemolymph. These cells most likely secreted the fluid involved in water vapor uptake by ticks. ForAmblyomma americanum females, abundant K⁺-dependent, ouabain-sensitive Na⁺, K⁺-ATPase complexes were located on the infolded basal plasma membranes of the lamellate cells. Apical membranes of the lamellate cells, and plasma membranes of other cell types in the acinus had little or no evidence of Na⁺, K⁺-ATPase activity. Only the central lamellate cell extended from the hemolymph of the acinus to its lumen; peripheral cells did not contact the lumen. Except when the ticks were rehydrating, lipid inclusions were common features in the lamellate cells of the ixodids. Lipid inclusions were not seen in argasid type I acini; however, glycogen deposits were common. To determine if acinar cells respond to the changing hydration state of the tick, unfed femaleA. americanum were subjected to dehydration/rehydrating conditions. During rehydration, mitochondria in the lamellate cells changed from a matrix of medium electron-density and intermembrane space (orthodox configuration) to a matrix of greater density and larger intermembrane space (condensed configuration). The orthodox configuration was consistently observed in control and dehydrating ticks. The condensed configuration was the norm for mitochondria in lamellate cells of rehydrating ticks. Lipid inclusions were depleted in the rehydrating ticks compared to control or dehydrating ticks. Acini appeared to be reverting to the control or desiccated state when ticks were returned to low humidity, suggesting that these changes were cyclical. Nymphs ofO. moubata subjected to the same dehydration/rehydrating conditions showed no obvious ultrastructural changes.     

Spontaneous cytotoxicity mediated by invertebrate mononuclear cells toward normal and malignant vertebrate targets: Inhibition by defined mono- and disaccharides

Spontaneous non-antigen-dependent cytotoxicity is displayed in vitro by mononuclear cells from molluscs, annelids, and echinoderms. The cytotoxic potential of these cells appears to be independent of prior antigenic exposure, is easily demonstrated in vitro, and is temperature dependent. The specificity of these cells may be directed at cell-surface glycoproteins on the target cell surface since a variety of defined mono- and disaccharides can block killing. The ability of sugars to block is target cell and effector cell specific. This finding is exactly analogous to our previous finding that human spontaneous monocyte-mediated cytotoxicity is blocked in a target-specific fashion by different mono- and disaccharides. These data suggest that invertebrate as well as vertebrate mononuclear cells may “recognize” targets through a series of sugar-specific “lectin-like” molecules present on the effector cell surface.     

Nucleotide pyrophosphatase of rat liver. A comparative study on the enzymes solubilized and purified from plasma membrane and endoplasmic reticulum.

Studies on the subcellular distribution of rat liver nucleotide pyrophosphatase activity revealed its presence in the plasma membrane and the endoplasmic reticulum only. The enzymes from either source were solubilized specifically with trypsin without an apparent change of their catalytic properties. A 200-fold and 1600-fold purification, respectively, was achieved by a procedure including DEAE-cellulose and affinity-chromatography with AMP as ligand, gel filtration on Sephadex G-200 and gel electrophoresis. Both nucleotide pyrophosphatases were isolated as electrophoretically homogeneous soluble proteins. They were shown to contain carbohydrate moieties. The electrophoretic mobility of both enzymes in polyacrylamide gels was identical at three pH values. Dodecylsulfate gel electrophoresis indicated a molecular weight of 137 000 for both glycoproteins. The enzymes hydrolyze a variety of purine and pyrimidine nucleotides yielding a 5'-nucleoside monophosphate. Adenosine 3':5'-monophosphate, nucleic acids and phosphate monoesters are not cleaved, but p-nitrophenyl-thymidine5'-monophosphate is readily hydrolyzed. In view of their substrate and inhibitor specificities the enzymes are considered nucleotide pyrophosphatases rather than phosphodiesterases.     

Author index for volume 219

Proteinase inhibitors I and II were purified to electrophoretic homogeneity from leaves of tomato plants induced by either wounding intact plants or by supplying excised plants with the proteinase inhibitor inducing factor. Affinity chromatography with chymotrypsin-Sepharose was employed as a final purification step for each inhibitor. The tomato leaf inhibitors are very similar to potato tuber inhibitors I and II in subunit molecular weight, composition, and inhibitory activities against chymotrypsin, trypsin, and subtilisin. However, unlike the potato tuber which contains multiple isoinhibitors by isoelectric focusing, the tomato leaf exhibits only two isoinhibitor forms of inhibitor I and a single form of inhibitor II. The molecular weight of native potato inhibitor I was reevaluated by rigorous ultracentrifugal analysis and compared with data from previous analyses. The data confirm that native inhibitor I has a native M_r of about 41,000 and is a pentamer. Inhibitor II has a molecular weight of near 23,000 and is a dimer.     

A mutant lymphoma cell line with a defectiveThy-1 glycoprotein gene

We characterized a mutant T -cell lymphoma line selected for the inability to express the Thy-1 glycoprotein. This cell line is a member of the D complementation class of Thy-1^– somatic cell mutants, and it lacks detectable cell-surface Thy-1.1 glycoprotein and detectable cytoplasmic Thy-1 mRNA. Southern blot analysis using a number of probes isolated from the clonedThy-1.2 gene demonstrated that, in the mutant, one copy of theThy-1 gene is absent from the genome and the other has undergone rearrangement. This rearrangement results from a deletion of the 5 portion of the gene removing the first two alternate exons and promoters and a portion of the second intron. The deletion breakpoint within the mutantThy-1 gene was localized to within 400 nucleotides by Southern blot analysis. The breakpoint is near two classes of mouse repetitive elements-a mouse B1-family repetitive element and a simple repetitive sequence-suggesting a mechanism of rearrangement leading to the mutation. Southern blot analysis demonstrated that two closely linked molecular markers on chromosome 9 are unaltered, demonstrating that the deletion in this mutant cell line is subchromosomal.