Generation of a purely clonal defective interfering influenza virus

Defective interfering (DI) influenza viruses carry a large deletion in a gene segment that interferes with the replication of infectious virus; thus, such viruses have potential for antiviral therapy. However, because DI viruses cannot replicate autonomously without the aid of an infectious helper virus, clonal DI virus stocks that are not contaminated with helper virus have not yet been generated. To overcome this problem, we used reverse genetics to generate a clonal DI virus with a PB2 DI gene, amplified the clonal DI virus using a cell line stably expressing the PB2 protein, and confirmed its ability to interfere with infectious virus replication in vitro. Thus, our approach is suitable for obtaining purely clonal DI viruses, will contribute to the understanding of DI virus interference mechanisms and can be used to develop DI virus‐based antivirals.     

Effect of Clostridium perfringens Beta Toxin on Blood Pressure of Rats

Guanethidine treatment or adrenal medullectomy significantly inhibited the elevation in blood pressure induced by Clostridium perfringens beta toxin, and the combination of the two drastically reduced the pressure rise, to less than 19% of that in control rats. When rats were pretreated with tetrodotoxin or hexamethonium, the toxin-evoked rise was significantly inhibited. Elevation in blood pressure induced by the toxin in spinal rats tended to be less than that in control rats. When investigated by a microscopical technique, arteriolar constriction in the mesenteric vasculature was observed after the blood pressure elevation induced by the toxin reached a maximum. Blood flow in the skin decreased with an increase in blood pressure following intravenous injection of the toxin. It is concluded that beta toxin acts on the autonomic nervous system and produces arterial constriction.     

Ring chromosome 15 in a mother and her children

Summary A case of ring chromosome 15 passed on to the index patient's two children is reported, and possible reasons for the infrequent records of inheritance of ring chromosome are suggested.     

PISTIL DEVELOPMENT AND PARIETAL PLACENTATION IN THE PSEUDOMONOMEROUS OVARY OF ZELKOVA SERRATA (ULMACEAE)

Development of female flowers in Zelkova serrata was observed using epi-illuminated microscopy and scanning electron microscopy, with particular attention given to placentation. After the inception of staminodial primordia, the floral apex becomes flat, and the first and subsequently the second carpel primordia appear at opposite comers of the pistil primordium. Inside each carpel primordium a fossette forms. Through differential growth this depression becomes clear and the carpel wall encircles one side of the future placental region. The placental region is detectable even in early stages, but clear signs of ovule inception appear late when the placental region is elevated onto one side of the ovary wall by intercalary growth. Although the relative size of the two carpels varies among flowers, the placental position always appears to be the border between the two carpels and the floral apex. This suggests that the placentation of Zelkova is parietal. The ovule position in tricarpellate ovaries also suggests an evolutionary derivation from ovaries with parietal placentation. Parietal placentation appears to be the original condition in Urticales.     

Histamine receptor effects on dissipation of an intracellular proton gradient of isolated gastric mucosal surface cells

The effects of histamine and several H1 and H2 receptor agents on Na+/H+ and Cl-/HCO-3 exchange systems of isolated gastric mucosal surface cells were studied. The cells were acid-loaded by the NH4Cl prepulse technique and the spontaneous Na+- and HCO-3-induced dissipation of the intracellular proton gradient (pHi) was followed using the metachromatic dye acridine orange. Histamine (10(-2-5) M) stimulates HCO-3-induced dissipation of the pHi but has no effect on Na+-induced or spontaneous dissipation. The H1 agonist 2-(2-aminoethyl)pyridine and the H2 agonist dimaprit also have no effect on Na+-induced or spontaneous pHi dissipation. However, both of these agents mimic the effect of histamine on HCO-3-induced dissipation, but only at a higher concentration (10(-3) M). The combination of 2-(2-aminoethyl)pyridine and dimaprit produces a histamine-like effect at lower concentrations (10(-5) and 10(-4) M). The effects of histamine are blocked by either the H1 antagonists diphenhydramine and pyrilamine or the H2 antagonists cimetidine and SKF 93479. The results suggest that the effect of histamine on HCO-3-induced dissipation of a pHi in gastric mucosal surface cells is mediated through a coordinated mechanism involving both H1 and H2 receptor sites.     

Interleukin-1 derived from human monocytic leukemia cell line JOSK-I acts as an autocrine growth factor

Interleukin-1 (IL-1) enhances the growth of human monocytic leukemia cell line JOSK-I cells, which were recently established in our laboratory and which were demonstrated to produce a high level of IL-1 constitutively, in liquid as well as semisolid culture systems. Concomitantly, IL-1 stimulated the prostaglandin E2 synthesis and nitroblue tetrazolium dye-reducing capacity of JOSK-I cells. This indicates that IL-1 may act as autocrine growth factor for monocytes, and also suggests the possibility that this autocrine stimulation may play an important role in the pathophysiology of monocytic leukemia in vivo.     

Application of coomassie brilliant blue staining to cultured hepatocytes

Coomassie brilliant blue staining developed by Pena (1980) was applied to cultured hepatocytes of adult rats with some modifications. Many of organelles in the cytoplasms were clearly visible as blue granules by this method. Various cytoskeletal elements were also visualized clearly. Because of its simplicity, Coomassie blue staining proved to be a very powerful tool for study of morphological changes of cell organelles and cytoskeletal systems of cultured hepatocytes.     

Structural study of the sugar chains of human platelet thrombospondin

The asparagine-linked sugar chains of human platelet thrombospondin were released as oligosaccharides by hydrazinolysis. About 12 mol of sugar chains was released from one thrombospondin molecule. This was converted to radioactive oligosaccharides by sodium borotritide reduction after N-acetylation, and separated into one neutral and four acidic fractions by paper electrophoresis. More than 90% of the oligosaccharides were recovered in the acidic fraction. The acidic oligosaccharides were mostly converted to neutral oligosaccharides by sialidase treatment, indicating that they are sialyl derivatives. The neutral and sialidase-treated acidic oligosaccharides were further fractionated by Bio-Gel P-4 column chromatography. Structural study of each oligosaccharide by sequential exoglycosidase digestion and methylation analysis revealed that the thrombospondin contains mono-, bi-, tri-, and tetraantennary complex-type sugar chains in addition to a small amount of high-mannose type. Approximately 70% of the complex-type sugar chains was fucosylated at asparagine-linked N-acetylglucosamine residue and 19% of the biantennary complex-type sugar chains was bisected.