Interleukin 2 acts directly on a Tac-positive cloned B cell line established from a patient with adult T cell leukemia

A Tac-positive B cell line termed K3B was established from a patient with adult T cell leukemia (ATL). This cell line had EBNA antigen and human T cell leukemic virus (HTLV) provirus besides B1 antigen and surface immunoglobulin. A cloned Tac-positive B cell line termed K3B01 was obtained from K3B by the limiting dilution method. The K3B01 cells were shown to absorb IL 2 activity in a tonsillar IL 2 preparation. By using this cloned cell line and a purified recombinant IL 2 preparation, it was shown that the proliferation of K3B01 cells was enhanced by the addition of recombinant IL 2. Moreover, this response was inhibited by anti-Tac antibody. These results demonstrate definitively that IL 2 acts directly on B cells through IL 2 receptors on them.     

X-ray crystallographic and chromatographic characterization of the crystals of Ca2+-calmodulin complexed with bee venom melittin

Crystals of calmodulin complexed with both Ca2+ and melittin, a peptide from bee venom, have been grown from 2-methyl-2,4-pentanediol solution by using the hanging drop method of vapour diffusion. The crystals belong to space group P2(1)2(1)2(1) with a = 97.3(9) A, b = 56.5(0) A, c = 33.4(9) A and Z = 4. Analyses of the dissolved crystals by high performance liquid chromatography show that the crystals contain a 1:1 complex of calmodulin and melittin. An asymmetric unit contains one such complex and the solvent content of the crystals is 47.5% (v/v).     

Attenuating effect of diazepam on stress-induced increases in noradrenaline turnover in specific brain regions of rats: antagonism by Ro 15-1788

One-hour immobilization stress increased levels of the major metabolite of brain noradrenaline (NA), 3-methoxy-4-hydroxyphenyl-ethyleneglycol sulfate (MHPG-SO4), in nine brain regions of rats. Diazepam at 5 mg/kg attenuated the stress-induced increases in MHPG-SO4 levels in the hypothalamus, amygdala, hippocampus, cerebral cortex and locus coeruleus (LC) region, but not in the thalamus, pons plus medulla oblongata excluding the LC region and basal ganglia. The attenuating effects of the drug on stress-induced increases in metabolite levels in the above regions were completely antagonized by pretreatment with Ro 15-1788 at 5 or 10 mg/kg, a potent and specific benzodiazepine (BDZ) receptor antagonist. When given alone, Ro 15-1788 did not affect the increases in MHPG-SO4 levels. Behavioral changes observed during immobilization stress such as vocalization and defecation, were also attenuated by diazepam at 5 mg/kg and this action of diazepam was antagonized by Ro 15-1788 at 10 mg/kg, which by itself had no effects on these behavioral measurements. These findings suggest: (1) that diazepam acts via BDZ receptors to attenuate stress-induced increases in NA turnover selectively in the hypothalamus, amygdala, hippocampus, cerebral cortex and LC region and (2) that this decreased noradrenergic activity might be closely related to relief of distress-evoked hyperemotionality, i.e., fear and/or anxiety in animals.     

Mutagenicity of N-acetyl and N,N'-diacetyl derivatives of 3 aromatic amines used as epoxy-resin hardeners

3 epoxy-resin hardeners, 4,4'-diaminodiphenyl ether (DDE), 4,4'-diaminodiphenylmethane (DDM), and 4,4'-diaminodiphenylsulfone (DDS), and their N-acetyl and N,N'-diacetyl derivatives were examined for their mutagenicity using Salmonella typhimurium TA98 and TA100 as the tester stains and an S9 mix containing a rat-liver 9000 X g supernatant fraction as the metabolic activation system. DDE and DDM were mutagenic towards TA98 and TA100 in the presence of S9 mix while DDS exhibited no significant mutagenic activity towards these tester strains. These epoxy-resin hardeners were metabolized in vivo and their N-acetyl and N,N'-diacetyl metabolites were found in the urine. Among these acetyl metabolites, only N-acetyl-DDE was found to be mutagenic towards TA98 and TA100 in the presence of S9 mix. None of these acetyl metabolites exhibited significant mutagenic activity towards these tester strains in the absence of S9 mix.     

O3 Tolerance and the Ascorbate-Dependent H2O2 Decomposing System in Chloroplasts

The relationship between O₃ tolerance and the chloroplast H₂O₂scavenging system (PS I     

Light Activation of NADP-Malate Dehydrogenase in Guard Cell Protoplasts from Vicia faba L

Light-induced swelling of guard cell protoplasts (GCP) from Vicia faba was accompanied by increases in content of K⁺ and malate. DCMU inhibited the increase of K⁺ and malate, and consequently swelling.

Effect of light on the activity of selected enzymes that take part in malate formation was studied. When isolated GCP were illuminated, NADP-malate dehydrogenase (NADP-MDH) was activated, and the activity reached a maximum within 5 minutes. The enzyme activity underwent 5- to 6-fold increase in the light. Upon turning off the light, the enzyme was inactivated in 5 minutes NAD-MDH and phosphoenolpyruvate carboxylase (PEPC) were not influenced by light. The rapid light activation of NADP-MDH was inhibited by DCMU, suggesting that the enzyme was activated by reductants from the linear electron transport in chloroplasts. An enzyme localization study by differential centrifugation indicates that NADP-MDH is located in the chloroplasts, NAD-MDH in the cytosol and mitochondria, and PEPC in the cytosol. After light activation, the activity of NADP-MDH in guard cells was 10 times that in mesophyll cells on a chlorophyll basis. The physiological significance of light-dependent activation of NADP-MDH in guard cells is discussed in relation to stomatal movement.

     

Inhibition of virus multiplication by immunoactive peptides

In the present study we show that peritoneal macrophages obtained from the mice treated with the immunoactive peptides inhibit the multiplication of Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), but not that of vesicular stomatitis virus (VSV), and that the intraperitoneal administration of the peptides suppresses the infection with HSV-1 in mice.     

Electron microscopical findings with special reference to cancer in rats caused by inhalation of nickel oxide

A special exposure system was used for the inhalation of nickel oxide (NiO) aerosol by Wistar male rats. The median aerodynamic diameter and the geometric standard deviation were 1.2 μm and 2.2, respectively. A histopathological study of the rats was performed immediately, and at intervals of 12 and 20 mo after a 1-mo expsoure to NiO. Electron microscopy showed that localization of NiO particles was restricted to the lungs and that each particle had been engulfed by the alveolar macrophages. Type II pneumocytes and nonciliated bronchiolar epithelial cells (Clara cells), as well as numerous tubular myelin (surfactant) in the alveoli were prominent. In rats dissected after 12 mo, clusters of NiO particles were still present within the terminal bronchioli, alveolar walls, and lysosomes of the alveolar macrophages. Pools of tubular myelin were observed in the peribron-chial lymphatics. The Clara cells, which project into the lumen of bronchioli, showed active secretion and were filled with smooth en-doplasmic reticulum (SER) in the apical cytoplasm. In the experimental group sacrificed after 20 mo, one rat had papillary adenocarcinoma and two rats showed adenomatosis in the peripheral portion of the lung, but none in the upper respiratory tract.     

Glucosylation of esculetin by plant cell suspension cultures

Cell suspension cultures of Lithospermum erythrorhizon, Gardenia jasminoides and Nicotiana tabacum were capable of glucosylating esculetin to esculin (7-hydroxycoumarin-6-O--D-glucoside). Especially, a culture strain of Lithospermum erythrorhizon was superior in the esculetin glucosylating capability; 40 to 50% of esculetin administered to the culture medium at early stationary growth stage was converted into esculin within 24 h. The rate of glucosylation was also dependent on the growth stage and the medium composition especially growth hormones and sugar.     

A versatile bacterial enzyme: l-methionine γ-lyase

The properties and application of l-methionine γ-lyase [methioninase, l-methionine methanethiol-lyase (deaminating), EC 4.4.1.11], a pyridoxal 5′-phosphate enzyme, purified from Pseudomonas putida and Aeromonas sp. are presented. The enzyme has multicatalytic functions: it catalyses α,γ-elimination and γ-replacement reactions of l-methionine and its analogues (e.g. ethionine, homocysteine, O-acetylhomoserine and selenomethionine), α,β-elimination and β-replacement reactions of l-cysteine and its analogues (e.g. S-methylcysteine, O-acetylserine and Se-methylselenocysteine), deamination and γ-addition of vinylglycine, and deuterium labelling at the α and β positions of l-methionine and other straight-chain l-amino acids. These reactions are applicable to the synthesis of various optically active sulphur and selenium amino acids, preparation of deuterium or tritium labelled l-amino acids, and determination of sulphur amino acids. In addition, the enzyme shows potent anti-neoplastic activity.