Real-Time Monitoring of Slow-Wave Sleep by Electroencephalogram Variance

Based on statistical variance as an index of electroencephalogram (EEG) parameters, we monitored slow-wave sleep in both humans and rats in real time and on-line with a widely used personal computer. This EEG variance method may be a useful tool to carry out biological rhythm research, including sleep studies.     

A point mutation at the putative ATP-binding site of protein kinase C alpha abolishes the kinase activity and renders it down-regulation-insensitive. A molecular link between autophosphorylation and down-regulation

A protein kinase C alpha (PKC alpha) cDNA confers increased phorbol ester binding activity to intact cells when transiently expressed in COS cells or expressed stably in transfected rat 3Y1 fibroblasts. A point mutant (PKC alpha K----R) of PKC alpha, where Lys368 at the putative ATP-binding site is replaced with Arg, confers enhanced phorbol ester binding activity to both transiently and stably expressed COS and 3Y1 cells, respectively. Like endogenous and exogenously expressed wild type PKC alpha, the mutant PKC alpha K----R is translocated from the cytosol to the particulate fraction when cells are treated with a phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA). On the other hand, the mutant PKC alpha K----R is not degraded when cells are treated with TPA, making a clear contrast to wild type PKC alpha; i.e. the mutant is resistant to TPA-mediated down-regulation. The mutant lacks kinase activity as expected, as judged by autophosphorylation and by a kinase assay using a peptide substrate, although the phorbol ester binding activity remains intact. These results suggest a link between the kinase activity of PKC alpha and the sensitivity to TPA-mediated proteolytic degradation. We propose that autophosphorylation of PKC alpha is a prerequisite for proteolytic cleavage associated with the down-regulation of PKC alpha.     

Two distinct cDNAs for human IMP dehydrogenase

IMP dehydrogenase (EC 1.1.1.205), the rate-limiting enzyme of de novo GTP biosynthesis, is a promising target in antileukemic chemotherapy. We have isolated two distinct cDNA clones (types I and II) encoding IMP dehydrogenase from a human spleen cDNA library. Both clones encode closely related proteins of 514 residues showing 84% sequence identity. Northern hybridization analyses of poly(A)+ RNA from human normal leukocytes and human ovarian tumors demonstrated a striking contrast in mRNA expression in that type I mRNA is the main species in normal leukocytes and type II predominates over type I in the tumor. This is the first report suggesting the existence of two distinct types of human IMP dehydrogenase molecular species which may have different sensitivities to the drugs targeted against IMP dehydrogenase.     

Pathological studies on encephalitis in mice experimentally inoculated with bovine coronavirus

One- to 21-day-old mice were examined pathologically after inoculated intracerebrally or subcutaneously with the Kakegawa strain of bovine coronavirus. In 1- to 4-day-old mice inoculated intracerebrally, the brain contained a small number of neutrophils and lymphocytes having infiltrated diffusely and perivascularly and some degenerative neurons. In mice inoculated intracerebrally at 7 to 21 days of age, severe necrosis of pyramidal cells was shown in Ammon's horn. Perivascular infiltrations of neutrophils and lymphocytes were moderate to severe. Some neurons were degenerative in the cerebral cortex, thalamus and midbrain. Degeneration of some neurons and mild infiltration of neutrophils and lymphocytes were observed in the brain of mice inoculated subcutaneously at 1 to 7 days of age. Perivascular infiltration of neutrophils and lymphocytes was prominent in the cerebral cortex of mice inoculated subcutaneously at 14 days of age. Cellular infiltration was also seen in the thalamus, Ammon's horn, midbrain, cerebellum and medulla oblongata. All the mice, except one, inoculated subcutaneously at 21 days of age were free from neural changes. Electron-microscopically, virus particles were observed in and outside of the degenerative neurons. They had a core 70 nm in diameter and an envelope with spikes.     

Studies on the Pectic Depolymerases I. Exopolygalacturonase from Root Tissues and Cell Suspension Cultures of Carrots

Three polygalacturonases (PG) have been isolated from carrots(Daucus carota L. cv. Kintoki). Two were isolated from roottissues (PG-I and PG-II) and one from cell suspension cultures(PG-III). PG-I and PG-III were readily solubilized in a lowionic strength buffer, whereas PG-II required additional NaClto be solubilized. These seems to be a change in the propertiesof PG between the original tissue and carrot cell cultures.The three PGs were partially purified by chromatography on SephadexG-150, and characterized. Elution from a Sephadex G-150 column indicated a molecular weightof about 48,000 for all three PGs. PG-III, studied in detail,hydrolyzed the galacturonan chain in an exo-fashion, and wasnot activated by a variety of cations at concentrations of 0.5or 1.0 mM. The pH optimum, and pH and heat stability of PG-Iand PG-III were slightly different from those of PG-II. PG-Iwas also different from PG-II and PG-III in its pectin hydrolyzingactivity. These results indicate that the enzymatic properties of PG-IIIfrom cell cultures are very similar to those of PG-I or PG-IIfrom root tissues; the only significant difference seems tobe the binding properties of the PGs to the cell wall materials. (Received March 23, 1981; Accepted June 11, 1981)     

Microflow system promotes acetaminophen crystal nucleation

It is known that interfaces have various impacts on crystallization from a solution. Here, we describe crystallization of acetaminophen using a microflow channel, in which two liquids meet and form a liquid–liquid interface due to laminar flow, resulting in uniform mixing of solvents on the molecular scale. In the anti‐solvent method, the microflow mixing promoted the crystallization more than bulk mixing. Furthermore, increased flow rate encouraged crystal formation, and a metastable form appeared under a certain flow condition. This means that interface management by the microchannel could be a beneficial tool for crystallization and polymorph control.     

Antimicrobial activity and secondary structure of a novel peptide derived from ovalbumin

A novel antimicrobial peptide derived from ovalbumin has been discovered. First, the peptide fragment RKIKVYLPRMK (TK9.1) was identified based on computerized predictions of the secondary structure of peptides in a protein data bank. Using HeliQuest, the sequence was developed into RKIKRYLRRMI (TK9.1.3), which was synthesized using Fmoc‐solid phase peptide synthesis, and found to have strongly antimicrobial activity against Gram‐positive and Gram‐negative bacteria, and fungi but not cytotoxic to HeLa cells and hemolysis in mouse red blood cells. Although ovalbumin itself does not have an antibacterial activity, our results suggest that it may supply the organisms that consume it with antimicrobial peptides, in support of their immunodefence.