Synthesis of a nonacosapeptide (beta-fragment) corresponding to the N-terminal sequence 1-29 of human liver metallothionein II and its heavy metal-binding properties

A nonacosapeptide (beta-fragment) corresponding to the N-terminal sequence 1-29 of human liver metallothionein II was synthesized by the fragment condensation method. The Cd-binding ability of the beta-fragment was much stronger than that of cysteine as thionein and synthetic alpha-fragment corresponding to the C-terminal sequence 30-61 of human liver metallothionein II. Both the alpha- and beta-fragments bound preferentially to Cu ions rather than Cd ions.     

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.     

Relative effectiveness and interaction of ultraviolet-B, red and blue light in anthocyanin synthesis of apple fruit

The effect of light on anthocyanin production in apple ( Malus pumila Mill. cv. Jonathan) skin disks was investigated, with prolonged irradiation from different light sources. High fluence rates of white light provided from a xenon lamp were unable to produce large amounts of anthocyanin, and anthocyanin production became saturated at about 30 W m⁻². When UV-B light, provided by a fluorescent lamp which had an emission peak at 312 nm, was combined with the white light, anthocyanin production was synergistically stimulated and increased up to the highest fluence rates of white light tested (44 W m⁻²). This UV-B light was more effective than red and blue light provided from fluorescent lamps, but anthocyanin production became saturated at about 1.7 W m⁻². However, simultaneous irradiation with red and UV-B light had a synergistic effect. UV-B light was also effective in increasing anthocyanin production in whole fruit. Therefore this synergism seemed to have an important role in the development of the desirable red skin color under field light conditions. The results of aminoethoxyvinylglycine treatment suggested that ethylene was not involved in the stimulative effect of UV-B light.     

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.

     

Stability enhancement and circular dichroism spectral anomaly as an indication of non-covalent interactions in histidine- and tyrosine-containing ternary copper(II)—amino acid systems

Visible absorption and CD spectral and potentiometric studies on the His- and Tyr-containing ternary copper(II) complexes Cu(A)(L-B), where A refers to L-His, D-His, or L-Tyr and B to Lys, Tyr, Trp, Phe, Ala, Val, Arg, Glu, Asn, Gln, Ser, or Thr, were made to study ligand-ligand interactions in the complexes. While the CD spectral magnitudes in the d—d region are additive in the absence of side chain interactions and can be estimated from the magnitudes for the ternary systems involving DL-A or DL-B, deviation from the additivity was observed for Cu(L-His)(L-B) (B = LysH, Tyr, Trp, or Phe) and Cu(L-Tyr)(L-Trp). From the stability constants determined at 25 °C and I = 0.1 M (KNO₃), the equilibrium constants, K, for the following hypothetical equilibria were calculated to be large (0.14–0.60) for formation of Cu(L-/D-His)(L-B)(B = Tyr or Trp) and Cu(D-His)(L-Phe) with Cu(en)(L-Ala) as standard: $Cu(A)(L?Ala)+Cu(en)(L?b)\stackrel{K}{?}Cu(A)(L?B)+Cu(en)(L?Ala)$ The positive values indicate the stabilization due to the stacking between the imidazole ring of His and the aromatic side chain of L-B. Solvent dependence of the CD spectra for Cu(L-His)(L-LysH) and Cu(L-His) L-Trp) further supported the existence of the intramolecular electrostatic and hydrophobic interactions.     

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.