Osage orange (Maclura pomifera): History and economic uses

Osage orange, a tree native to Texas, Oklahoma, and Arkansas, was planted widely in the United States as a living fence from 1850–1875. It has naturalized over much of its planted range and is an early successional species. Economically the tree has had a wide number of uses including for bows, yellow dye, and building materials. It is used for fence posts and is a potential source for a proteolytic enzyme. Its taxonomy, anatomy, morphology, chemical constitutents, medicinal uses, and toxicity are discussed in this paper and related to its economic importance.     

Electrical correlates of secretion in endocrine and exocrine cells

Many types of secretory cells including neurons and cells of endocrine and exocrine glands show changes in electrical potential and resistance when secretion is stimulated. These electrical correlates result from the movement of ions across the cell membrane through specific ion-selective channels. In neurons and certain endocrine cells (such as pancreatic beta cells and certain cells of the anterior pituitary), these channels are voltage dependent and open transiently upon depolarization leading to action potentials. Thus some endocrine cells are electrically excitable, a property previously held to occur only in nerve and muscle. In other nonexcitable endocrine and exocrine cells (such as the pancreas and parotid), ion channels are responsive to either occupancy of specific membrane receptors or changes in intracellular metabolites and second messengers. Ion fluxes through these latter channels also lead to changes in the electrical potential and resistance, but these changes are generally more sustained and action potentials are not seen. The entry of Ca2+ through both voltage-dependent and voltage-independent ion channels plays a major role in the activation of secretion via exocytosis.     

Histochemical characteristics of spontaneous and chemically induced hepatocellular neoplasms in mice and the development of neoplasms with gamma-glutamyl transpeptidase activity during phenobarbital exposure

Summary The histochemical characteristics of spontaneous hepatocellular neoplasms in mice of both sexes were examined and compared with those of hepatocellular neoplasms induced in female mice by administration of polycyclic aromatic hydrocarbon carcinogens as initiators with or without subsequent phenobarbitone treatment. Controls treated with phenobarbitone alone were also included. Spontaneous neoplasms in the livers of mice rendered siderotic by subcutaneous iron injection were deficient in cellular accumulation of stainable iron. Glucose-6-phosphatase activity was deficient in the majority of spontaneous and induced neoplasms. ATPase activity was increased in about half of spontaneous and carcinogen-induced neoplasms but all induced neoplasms in mice treated with phenobarbitone showed deficient activity. -Glutamyltransferase activity was present in very few of the spontaneous neoplasms or in the neoplasms induced in the absence of phenobarbitone administration. However, all induced neoplasms in the mice receiving phenobarbitone showed some degree of -glutamyltransferase activity together with deficient glucose-6-phosphatase and ATPase activities. It is concluded that the histochemical characteristics of spontaneous or induced mouse hepatocellular neoplasms are variable and may be influenced by the inducing factors.     

Evaluation of a standpipe corer for sampling aquatic interstitial biotopes

The relative efficiencies of two sizes of a standpipe corer were evaluated. The size composition of the gravel sampled by the corer was very similar to that (below the opening size of the core chamber) of the streambed. The small corer (25 cm³ sample size) produced a mean overestimate of total numbers of only 19% even in highly heterogeneous gravels. Most of the taxa commonly in the substrates sampled did not escape from the corer. A few rare taxa were consistently over- or under-estimated and possible reasons for this are discussed.     

Invertebrate drift lost to the sea during low flow conditions in a small coastal stream in Western Canada

The invertebrate drift leaving the lower end of a small coastal stream on the east coast of Vancouver Island was recorded during low flow conditions. 20,156 animals, weighing 0.96 g (dry weight), were collected in drift nets over a 5 day period in early summer. High and low drifting taxa are listed. Considerable daily variation in total captures occurred and was attributed to a few dominant taxa (primarily harpacticoid copepods, mites and chironomid larvae) exhibiting atypical drift patterns. 0.004% of the stream's invertebrate standing crop was estimated to be in the water column at any instant in time. The possible use of the outgoing animals as food for juvenile salmon in the estuary is discussed.     

Mode of action of somatostatin in inhibiting parathyroid hormone secretion

Effects of somatostatin on basal and low calcium-, isoproterenol- or dibutryl cyclic AMP (DBcAMP)-stimulated parathyroid hormone (PTH) secretion were evaluated in vitro with bovine parathyroid tissue. Low calcium, isoproterenol or DBcAMP alone significantly stimulated PTH secretion. Somatostatin 1 or 4 microgram/ml significantly inhibited these stimulated PTH secretions. Inhibition of isoproterenol-stimulated PTH secretion was more complete than was the inhibition of low calcium- or DBcAMP-stimulated secretion. The studies indicate that somatostatin inhibits PTH secretion by an action distal to cAMP generation. The more complete inhibition of isoproterenol-stimulated PTH secretion suggests that somatostatin may also have additional effects on or proximal to the formation of cyclic AMP.     

Precise Mapping of the Homothallism Genes HML and HMR in SACCHAROMYCES CEREVISIAE

The HML and HMR loci carry unexpressed copies of MATa and MATα information, and a replica of that information is transposed to MAT during mating-type interchange in Saccharomyces yeasts. A negative control mechanism keeps silent the information located at the HML and HMR loci. We mapped these loci by constructing strains in which these loci are expressed. In these strains, the mating type of the segregants is dependent upon the allele at HML and HMR. This novel approach is independent of their switching function. HML is located on the left arm of chromosome III distal to his4 by about 26.8 centimorgans (cM). HMR maps on the right arm of the same chromosome distal to thr4 by about 39.8 cM and proximal to MAL2 by about 1.0 cM. The results allow the exact placement of these loci and are in accord with the observations made by Harashima and Oshima (1976).