Thermal stability of carp G-actin monitored by loss of polymerization activity using an extrinsic fluorescent probe

ABSTRACT:   The thermal stability of carp G-actin was investigated by monitoring loss of actin polymerization ability. To determine the amount of native actin remaining after heat treatment, actin was labeled with a fluorescence reagent, N-(1-pyrene)iodoacetamide. The loss of polymerization ability of carp actin during heat treatment, at between 45 and 55°C, occurred faster than that of chicken actin. The inactivation rate was influenced by concentrations of ATP and Ca²⁺ in solution. With the increase of Ca²⁺ concentration, the inactivation of carp actin was markedly suppressed. Furthermore, the activation energy of the inactivation of carp actin obtained from an Arrhenius plot was similar to that of chicken actin. These results indicated that the thermal instability of carp G-actin was due to the low affinites of ATP and Ca²⁺ for carp actin described in a previous report.     

Dietary apigenin suppresses IgE and inflammatory cytokines production in C57BL/6N mice

Flavonoids ubiquitously exist in plants, vegetables, fruits, and teas. We evaluated the effect of dietary apigenin, one of the well-known flavonoids, on the immune system in C57BL/6N mice. Mice were fed experimental diets containing apigenin for 2 weeks. After the experimental period, there was no significant difference in body and organ weights between the control and the apigenin group. The total immunoglobulin (Ig) E levels in mice fed apigenin were significantly suppressed, whereas levels of IgG, IgM, and IgA were not affected. We also examined the effect of the apigenin diet on cytokine expression in mice sera using a cytokine array. The production of regulated upon activation normal T cell expressed and secreted (RANTES) and soluble tumor necrosis factor receptor I (sTNFRI) in mice sera was down-regulated by the apigenin diet. These results suggest that a diet containing apigenin can reduce serum IgE and inflammatory cytokines such as RANTES and sTNFRI in mice.     

Compressive deformation of wood impregnated with low molecular weight phenol formaldehyde (PF) resin III: effects of sodium chlorite treatment

To obtain high-strength phenol–formaldehyde (PF) resin-impregnated compressed wood at low pressing pressure, we investigated the effects of sodium chlorite (NaClO₂) treatment on wood prior to low molecular weight PF resin impregnation. Sawn veneers of Japanese cedar (Cryptomeria japonica) were treated with 2% aqueous NaClO₂ solution at 45°C for 12 h to remove lignin, and the process was repeated up to four times, resulting in weight loss of 21%. NaClO₂ treatment has shown considerable potential for high compression of PF resin-impregnated wood at low pressing pressure, especially after adding moisture to a content of 10%–11%. This deformation is further enhanced during pressure holding by creep deformation. The density, Young’s modulus, and bending strength of PF resin-impregnated veneer laminated composites that were treated with NaClO₂ four times and compressed at 1 MPa, reached 1.15 g/cm³, 27 GPa, and 280 MPa, respectively. The values in untreated PF resin-impregnated wood reached 0.8 g/cm³, 16 GPa, and 165 MPa, respectively.     

Influence of osmotic pressure on somatic embryo maturation in Pinus densiflora

The effect of an osmoticum, polyethylene glycol (PEG), on somatic embryo production was examined using embryogenic cells of Pinus densiflora. In the basal medium containing 30 μM abscisic acid and 6% maltose, the quality of the embryos formed was poor even though somatic embryos were produced. The addition of PEG with molecular weight of 4000 or 8000 significantly enhanced the development of both the quality and quantity of somatic embryos. Furthermore, higher levels of a constant osmotic pressure with PEG 8000 in a range from about 300 to 450 mmol/kg could remarkably enhance the morphogenesis of somatic embryos and their number of embryos produced. A higher stable osmotic pressure with an appropriate molecular weight of PEG is a key factor for the production of good quality somatic embryos in P. densiflora.     

Newly developed nanocomposites from cellulose acetate/layered silicate/poly(ε-caprolactone): Synthesis and morphological characterization

New biodegradable cellulose acetate/layered silicate grafted poly(ε-caprolactone) [(CA/layered silicate)-g-PCL] nanocomposites were prepared by in situ polymerization of ε-caprolactone in the presence of cellulose acetate (CA) and organically modified layered silicate (OMLS). The structures of the resulting composites were investigated. X-ray diffractometry was carried out to survey general structural features of (CA/OMLS)-g-PCL nanocomposites, and revealed that OMLSs having hydroxyl groups in the organic modifiers greatly altered the layered silicate structure by monomer intercalation and successive exfoliation through its polymerization. Two of the representative cases were characterized by wide-angle and small-angle X-ray scattering analyses with a synchrotron source. The morphology of these nanocomposites was further examined by transmission electron microscopy. When SPN, one of OMLSs having one hydroxyl group in its modifier, was used, the silicate layers could not be dispersed thoroughly, but existed as aggregates consisting of several silicate layers. Among them, the crystal growth of PCL developed by transcrystallization, where the crystal growth was restricted in the confined space. When Cloisite 30B, having two hydroxyl groups within the modifier, was used, the silicate layers forming the clay were dispersed completely in the composite and random orientation of the OMLS was observed.     

Use of trioxane for improvement of hygroscopic and acoustic properties of wood for musical instruments

Summary As a reagent source for the formalization of wood, trioxane was used instead of conventional paraformaldehyde. From preliminary experiments it became apparent that trioxane depolymerizes to formaldehyde by heating in the presence of some metallic salts. Formalization of wood with trioxane was carried out under the catalysis of sulfur dioxide (SO₂) along with these salts. The hygroscopic and acoustic properties were considerably improved by the treatment. Especially when the reaction was catalyzed by a combination of SO₂ and Fe₂(SO₄)₃, the antiswelling efficiency (ASE) reached nearly 70%, the specific dynamic Young's modulus (E/) in the radial direction increased about 20%, and the loss tangent (tan ) decreased about 30% and 50% in the longitudinal and radial directions, respectively. In this case, the modulus of rupture did not appreciably decrease in the radial direction. This is comparable to the most prominent results obtained so far by SO₂ catalyzed formalization with tetraoxane. It can be concluded that trioxane is very effective as a reagent source for formalization. The increase in acoustic converting efficiency, , of about twofold in the radial direction and decrease in hygroscopicity of more than 60% should not only enrich the sound volume of musical instruments but also stabilize their tone quality against humidity changes.     

Formation of the thiocyanate conjugate of chlorogenic acid in coffee under acidic conditions in the presence of thiocyanate and nitrite: possible occurrence in the stomach

The objective of the present study was to elucidate how chlorogenic acid in coffee was transformed under acidic conditions simulating the mixture of saliva and gastric juice. When coffee was incubated in acidified saliva that contained nitrite and SCN-, in addition to nitric oxide (NO), four major components were detected. Two of the four components (components 3 and 4) were generated when chlorogenic acid was incubated in acidified saliva and when incubated in an acidic buffer solution in the presence of both nitrite and SCN-. By the incubation of chlorogenic acid in acidic nitrite in the absence of SCN-, components 3 and 4 were not formed but the quinone of chlorogenic acid and nitrated chlorogenic acid were formed. The result indicates that SCN- was indispensable for nitrous acid induced formation of components 3 and 4. Component 4 was isolated and its structure was determined to be (E)-5'-(3-(7-hydroxy-2-oxobenzo[d] [1,3]oxathiol-4-yl)acryloyloxy)quinic acid. Component 3, which was suggested to be 2-thiocyanatochlorogenic acid, seemed to be formed by the reaction between SCN- and the quinone of chlorogenic acid. As it has been reported that the quinone of chlorogenic acid can react with thiols and can decompose producing H2O2, the formation of component 4 can reduce the toxic effects of the quinone of chlorogenic acid.     

The histopathogenesis of paralytic rabies in six-week-old C57BL/6J mice following inoculation of the CVS-11 strain into the right triceps surae muscle

A fatal encephalomyelitis was developed after intracerebral and hind limb inoculation of in 6-week-old C57BL/6J mice by the inoculation of fixed rabies virus (CVS-11 strain), intracerebrally and into hind. After the intracerebral inoculation, virus antigens were detected in the cerebral cortex and hippocampus at 2 days postinoculation (PI), and later spread centrifugally to thalamus, brain stem, cerebellum, spinal cord and spinal ganglia. At 4 days PI, severe apoptosis and DNA fragmentation were observed in the hippocampus and cerebral cortex. All mice infected intracerebrally were dead without limb paralysis at from 10 to 11 days PI. In contrast, mice infected with virus intramuscularly were persistently observed virus antigens in the myocytes at the site of inoculation from 2 days PI. At 4 days PI, the antigens were demonstrated in the spinal dorsal root ganglia, spinal cord and muscle spindles without their detection in the cerebrum and hippocampus. There were no apoptosis in the spinal cord and dorsal root ganglia, however hind limb paralysis was found in all infected mice. Hind limb paralysis was progressed to quadriparalysis, and mice were dead from 11 to 13 days PI. From 4 days PI, necrosis of neuron was observed in the the spinal and dorsal ganglia with infiltration of lymphocyte. This study suggested that the necrosis of spinal neurons was more important to cause the paralysis of hind limb rather than the severe cerebral infection and apoptosis in C57BL/6J mice infected with CVS-11 strain. The virus primarily replicated in the muscles was ascended the spinal cord via afferent fibers and retrogradely invaded the cerebrum, and with subsequent spread to muscle spindles.