Myofibrillar proteolysis in chick muscle cell cultures during heat stress

The effect of heat stress on protein oxidation and myofibrillar proteolysis in chick myotubes was investigated. Myotubes were incubated at 37 or 41°C for 6 and 24 h. Protein carbonyl content, as an index of protein oxidation, increased more at 41°C than at 37°C for 6 and 24 h incubations. N^τ‐methylhistidine release as an index of myofibrillar proteolysis also increased more at 41°C than at 37°C for 6 and 24 h incubations. Proteasome activity also increased more under those same conditions. Calpain and cathepsin D but not B + L activities showed a greater increase at 41°C than at 37°C for 24 but not the 6 h incubation. These results indicate that heat stress increases protein oxidation and proteasome activity, resulting in an increase in myofibrillar proteolysis for short‐term incubation and, for long‐term incubation, it increases calpain, proteasome and cathepsin D activities, finally accelerating myofibrillar proteolysis in chick myotubes.     

Flow cytometric analysis of chicken NK activity and its use on the effect of restraint stress

Immune system is organized by the influence of both neural and endocrine systems. NK activity plays an important role in the innate immunity. In this study, we observed the effects of restraint stress on chicken peripheral blood NK activity. Viability of FITC-labeled RP9 was measured with PI after treatment with the effector cells. Chicken peripheral blood CD8alpha+ cells expressed strong cytotoxic activity, in contrast to thrombocytes, while peripheral blood CD3+ CD8alpha+ cells and CD4+ cells had little cytotoxic activity. Con A supernatant enhanced the cytotoxic activity of CD8alpha+ cells. Therefore, it is considered that these cytotoxic activities measured by flow cytometry (FCM) analysis are NK activity. When chickens were exposed to restraint stress, the levels of serum corticosterone increased transiently over a short period of time while the NK activity decreased. The decreased NK activity, however, did not recover to the intact levels for a long time, even once the serum corticosterone levels had recovered. These data indicate that chicken NK activity is able to be measured by flow cytometric analysis and that restraint stress causes severe damage to the chicken NK activity.     

Identification of Trichoderma SKT-1, a biological control agent against seedborne pathogens of rice

Trichoderma SKT-1 was previously reported as a powerful biological control agent against seedborne pathogens of rice, but the taxonomic disposition of the fungal isolate was not clear. Trichoderma SKT-1 produced irregular pyramidal warts on conidia and had an optimum growth temperature of 30°C. Morphological characteristics and colony growth were identical to those of known species of Trichoderma, including the newly recognized species T. asperellum. The 5.8S rDNA with the internal transcribed spacer (ITS) region (ca. 514 bp) of the fungus was compared with those of known species to determine the phylogenetic placement of the fungus. The length and sequence of the regions from Trichoderma SKT-1 were completely identical to those of an isolate of T. asperellum NRRL 5242 (AJ230669). On the basis of these results, we concluded that Trichoderma SKT-1 was T. asperellum.     

A comparative pathological study on canine necrotizing meningoencephalitis and granulomatous meningoencephalomyelitis

Canine necrotizing meningoencephalitis (NME) and granulomatous meningoencephalomyelitis (GME) were compared pathologically. Gross observation exhibited lateral ventricular dilation and discoloration, malacia and/or cavitation of the cerebrum in NME. On the contrary, gross changes were milder in GME, except for occasional visible granulomatous mass formation. Histopathologically, the lesions of NME were distributed predominantly in the cerebral cortex and various degrees of inflammatory and necrotic changes were observed according to clinical stages. Besides, microscopic lesions of GME were mainly distributed in the white matter of the cerebrum, cerebellum and brainstem, which are characterized by perivascular cuffing, multiple granulomas and leptomeningeal infiltrates. Although macrophages and lymphocytes were predominant in the inflammatory lesions of both disorders, macrophages in GME transformed into epithelioid cells and exhibited more massive infiltration. Although lectin RCA-1-reactive cells were numerous in both disorders, lysozyme immunoreactive cells in NME were fewer than that in GME. Parenchymal infiltration of MAC387-positive cells was common in GME and limited in NME. The number of CD3-positive lymphocytes in the GME lesions tended to be greater than in NME, though the difference was not statistically significant. Morphological and immunohistochemical differences of the lesions, in particular, the characteristics of infiltrative macrophages may reflect these different pathogeneses of the two disorders.     

Micronutrients affecting adipogenesis in beef cattle

Beef marbling is an important trait of meat quality and beef marbling influences the tenderness and flavor of beef, which contributes directly to the value of beef especially in the Japanese market. The lipid content of beef depends on the strain, sex, diet and fattening period of the animal. Japanese Black cattle (Wagyu) are well‐known for their ability to produce marbling beef and this is a popular strain in Japan. The development of beef marbling was closely associated with an increase in the number of adipocytes, that is, adipocyte differentiation in the skeletal muscle. This review article describes our experiment and related reports on micronutrients, especially vitamins and minerals, affecting adipogenesis in beef cattle. We pursue the possibility that manipulating the level of dietary micronutrients may become a new technique to promote beef marbling.     

Durability evaluation of particleboards by accelerated aging tests

Summary Specimens of four commercially produced particleboards were exposed to various accelerated aging treatments: 1) 6-cycle ASTM D-1037 exposure, 2) 6-cycle WCAMA exposure, 3) BS 5669 test, 4) cyclic soak-dry test, and 5) cyclic boil-dry test. Thickness swelling (TS) and internal bond strength (IB) were measured after each step of each cycle. Phenol and phenol (face)/isocyanate (core)bonded boards are more durable than urea and melamine urea bonded boards. The effect of treatment 1) is most severe on TS and IB retention, followed in order by treatments 2), 5), 4) and 3). When the value of springback reached about 35%, IB became equal to zero.     

The influences of boiling and drying treatments on the behaviors of tension wood with gelatinous layers in <Emphasis Type="Italic">Zelkova serrata</Emphasis>

This study examined how boiling and drying treatments influenced various physical properties of the tension wood with gelatinous fibers (G-fibers) of a 29-yearold Zelkova branch. By boiling treatment, tension wood with numerous G-fibers contracted considerably in the longitudinal direction and the longitudinal Young’s modulus decreased in spite of the water-saturated condition. The drying treatment caused green tension wood and boiled tension wood with numerous G-fibers to shrink longitudinally and increased their longitudinal Young’s moduli. These specific behaviors in tension wood were highly correlated with the proportion of G-fibers in a specimen and were probably caused by the microscopic behavior of cellulose microfibril (CMF) in the gelatinous layers (G-layers). The longitudinal shrinkage of tension wood due to drying suggests the existence of a hygro-sensible, noncrystalline region in the CMF, which is abundant in the G-layer. Furthermore, the noncrystalline region in the CMF softens during boiling treatment, resulting in the reduction of the longitudinal Young’s modulus in tension wood. The longitudinal contraction of tension wood with G-fibers by boiling might be caused by the tensile growth stress remaining in green G-layers. However, no changes were detected in the 004 d-spacing of cellulose crystal in tension wood from the boiling and drying treatments, regardless of the proportion of G-fibers.     

Condensation reactions of phenolic resins V: cure-acceleration effects of propylene carbonate

Propylene carbonate (PC) is known as one of the cure accelerators for alkaline phenol–formaldehyde resins. To elucidate the cure-acceleration mechanisms, the effects of PC on the condensation reactions of monomeric hydroxymethylphenols (HMPs) were investigated and compared with those of PC hydrolysate, sodium bicarbonate (NaHCO₃) and ethyl formate. Immediately after the reaction started, PC, decomposing itself simultaneously, accelerated the formation of the ortho-para methylene-bonded dimer of 2,4,6-trihydroxymethylphenol. This effect of PC was very similar to that of ethyl formate. To the contrary, PC hydrolysate accelerated the formation of the para-para methylene-bonded dimer throughout the course of the reaction. This effect of PC hydrolysate was identical to that of NaHCO₃. These results indicate that PC increases the reactivity of the ortho-hydroxymethyl group, presumably through transesterification. On the other hand, NaHCO₃ is formed by the hydrolysis of PC or decomposition of the transesterified HMPs and it increases the reactivity of the para-hydroxymethyl group.