Regulation of muscular glutamate metabolism by high‐protein diet in broiler chicks

The major taste active component, glutamate (Glu), improves the taste of meat. In this study, we investigated the effect of a short‐term high‐protein (HCP) diet on the intramuscular free Glu content to improve the taste of meat. Furthermore, we elucidated how the muscle free Glu content was controlled by the HCP diet. Chicks (14 days old) were fed the control diet or HCP diet for 10 days. Plasma and muscle free amino acid concentrations, and activity and messenger RNA (mRNA) expression of muscle enzymes related to Glu metabolism were determined. Muscle free Glu content was increased (P < 0.01) by 51%. Activity and mRNA expression of glutaminase (GA), which is one of the major Glu‐related enzymes, were significantly decreased (P < 0.05) in the HCP group because of feedback inhibition. The mRNA expression of lysine α‐ketoglutarate reductase (LKR), which is the enzyme involved in lysine (Lys) degradation and Glu production, was significantly increased (P < 0.001) in the HCP group. These results suggest that short‐term dietary HCP feeding is an effective treatment for improving the taste of meat. Furthermore, our results suggest that the free Glu content in muscle is regulated by GA and LKR.     

Local photodynamic therapy for equine squamous cell carcinoma: evaluation of a novel treatment method in a murine model

The objective of this study was to evaluate the effect of local photodynamic therapy (PDT) with verteporfin on tumor growth inhibition of squamous cell carcinoma (SCC) in a murine model. SCC was implanted in 85 nude mice by subcutaneous injection of A-431 SCC cells. Treatment groups (10 mice/group) received an intra-tumoral injection of verteporfin dissolved in dimethyl sulfoxide (DMSO) or 5% dextrose solution at a dose of 0.01 or 0.1mg/cm3. Controls received only solvent, or no injectate. All groups received identical light illumination (100J/cm2). Relative change in tumor volume (RCTV) at day 30 was compared between groups using the Wilcoxon rank sum test (P< 0.05). Local PDT with verteporfin at a dose of 0.1mg/cm3 resulted in significantly lower RCTV at day 30 compared to controls. Choice of solvent (DMSO versus D5W) did not affect the results. Local PDT may be an effective adjunctive therapy for the treatment of periocular equine SCC.     

Effect of support on the growth of a woody vine,Wisteria floribunda DC. (Leguminosae)

Seedling ofWisteria floribunda, which belongs to the twiner type of climbing plants, were planted in nursery and the effect of support on the growth of the seedlings was tested. The seedlings were grown with 240 cm-height and 120 cm-height supports (the culms of a dwarf bamboo), and without support. Positive effect of the supports and its length were observed for stem length ofW. floribunda at the end of the growing season. The positive effect of support was also observed for total dry weight. Total dry weight with 240 cm-height support reached more than the double of the seedlings without support. These effects of the support were attributed to die-back behavior of the twining stem, which detached from the support or did not encounter the support. Diameter of the stems without support showed a rapid decrease toward the stem tip, while that with support were relatively constant when they were twining around the support. The existence of the support also affected the dry matter allocation in this species; supported seedlings allocated larger proportion of biomass to current-year stems than unsupported seedlings, although the allocation to the roots was smaller in the supported treatments. Support availability may be critical for the establishment and further growth of the seedlings ofW. floribunda which regenerate at the forest edge and canopy gaps. A part of this report was presented at the 107th Annual Meeting of the Japanese Forestry Society, at Tsukuba, April, 1996.     

Effect of plastic-film mulching on leaching of nitrate nitrogen in an upland field converted from paddy

A lysimeter experiment was conducted to examine the effects of plastic film mulching on the leaching rate of nitrate nitrogen (NO₃-N) from chemical fertilizer that was applied to an upland field that had been converted from paddy rice production. Leaching was monitored in two lysimeters filled with sandy loam soil, which contained low soil organic matter content, under different surface mulch conditions. One was mulched only on the ridge (ridge-mulch treatment) and another one was mulched fully, including the furrow, with black plastic film (full-mulch treatment). Chemical fertilizer was mixed into the top 0.2 m of soil in the two lysimeters before installing the mulch. After transplanting broccoli, the amount of subsurface discharge water and the NO₃-N concentrations in the discharge water were measured every day. Larger NO₃-N discharges occurred in the ridge-mulch treatment for three days after heavy rainfalls in which cumulative precipitation exceeded 10 mm, and the daily NO₃-N load was twice as large as the full-mulch treatment. The differences in the amount of subsurface discharge water and NO₃-N discharged between treatments were not significant when there was no rainfall. Cumulative NO₃-N loads for the ridge- and full-mulch treatment during the last month of the experimental period were 0.246 and 0.195 g m^–2, respectively. The effect of mulching on the reduction of NO₃-N discharge rate was higher for the full-mulch treatment. This result showed that a plastic-film mulching system would be effective as an appropriate fertilizer management to reduce nitrate-leaching losses.     

Class I hydrophobin BcHpb1 is important for adhesion but not for later infection of <Emphasis Type="Italic">Botrytis cinerea</Emphasis>

Hydrophobins are small secreted proteins unique to filamentous fungi. In this study, we cloned and characterized the class I hydrophobin gene BcHpb1 in the necrotrophic pathogen Botrytis cinerea. The BcHpb1 protein consisted of 117 amino acids. Similar to class I hydrophobins from other fungi, BcHpb1 contains eight conserved cysteine residues. The hydropathy plot of the BcHpb1 amino acid sequence was characteristic of a class I hydrophobin. These results indicated that the BcHpb1 gene encodes a class I hydrophobin. Vegetative growth of ΔBcHpb1 strains, null mutants of BcHpb1, was similar to that of the wild-type strain as were the conidiophores, conidia, appressoria and virulence on host plants. However, adherence of ΔBcHpb1 strains to hydrophobic surfaces was greatly reduced, implying that BcHpb1 is important for the hydrophobicity of conidia and that BcHpb1 may be required to adhere to plant surfaces under certain environmental conditions.     

Occurrence of chrysanthemum virescence caused by “<Emphasis Type="Italic">Candidatus</Emphasis> Phytoplasma aurantifolia” in Okinawa

In 1999, a disease of chrysanthemum [Dendranthema grandiflorum (Ramat.) Kitamura], characterized by virescence of flowers, occurred in Okinawa Prefecture. The causal agent was identified as “Candidatus Phytoplasma aurantifolia” based on 16S rDNA sequencing. The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under accession number AB247462.     

Lesion-based analysis of leaf blast suppression in mixture of rice cultivar and a resistant near-isogenic line

Leaf blast suppression in multilines was evaluated based on the number of susceptible lesions observed in a pure stand of susceptible rice cultivar Sasanishiki, and in 1 : 1 and 1 : 3 mixtures of Sasanishiki and a resistant near-isogenic line, Sasanishiki BL4 or BL7, from 1998 to 2001. The number of lesions first observed in fields in the 1 : 1 and 1 : 3 mixtures were close to theoretical numbers calculated using the number of lesions observed in the pure stands and the ratios of the susceptible Sasanishiki in the mixtures. The ratio of the number of lesions in the 1 : 1 and 1 : 3 mixtures to the number in the pure stand was 0.29 and 0.09, respectively. The relationship between these ratios and the ratios of susceptible Sasanishiki in mixtures was defined in an equation to estimate the degree of leaf blast suppression. Validation studies for the ratios of the number of lesions in the 1 : 1 and 1 : 3 mixtures to the number in the pure stand were conducted in two different locations and showed that the ratios are almost acceptable. The calculated autoinfection to alloinfection ratio was 1.3 and 1.4 in the 1 : 1 and 1 : 3 mixtures, respectively, suggesting that the calculated ratio will affect the degree of leaf blast suppression. Thus, predictors were obtained to estimate leaf blast suppression for effective blast control in multilines.     

Induction of Soil Suppressiveness Against Rhizoctonia solani by Incorporation of Dried Plant Residues into Soil

ABSTRACT Suppressive effects of soil amendment with residues of 12 cultivars of Brassica rapa on damping-off of sugar beet were evaluated in soils infested with Rhizoctonia solani. Residues of clover and peanut were tested as noncruciferous controls. The incidence of damping-off was significantly and consistently suppressed in the soils amended with residues of clover, peanut, and B. rapa subsp. rapifera 'Saori', but only the volatile substance produced from water-imbibed residue of cv. Saori exhibited a distinct inhibitory effect on mycelial growth of R. solani. Nonetheless, disease suppression in such residue-amended soils was diminished or nullified when antibacterial antibiotics were applied to the soils, suggesting that proliferation of antagonistic bacteria resident to the soils were responsible for disease suppression. When the seed (pericarps) colonized by R. solani in the infested soil without residues were replanted into the soils amended with such residues, damping-off was suppressed in all cases. In contrast, when seed that had been colonized by microorganisms in the soils containing the residues were replanted into the infested soil, damping-off was not suppressed. The evidence indicates that the laimosphere, but not the spermosphere, is the site for the antagonistic microbial interaction, which is the chief principle of soil suppressiveness against Rhizoctonia damping-off.     

Permeation of urea through various polyurethane membranes

BACKGROUND: Controlled‐release systems using polymer membranes are very important in agriculture for labour‐saving and effective delivery of pesticides and other agents. Polymer‐coated granules are one of the most useful formulations, and a study of the factors for polymer design is necessary to achieve various release patterns. A permeation study using plain membranes was carried out in order to clarify parameters, and the results were compared with the release from polymer‐coated granules. RESULTS: The permeation coefficient of urea through a plain polyurethane membrane decreased significantly as the urethane and alkyl side chain content increased. The glass transition temperature and crosslink density of the polyurethanes hardly influenced its permeability. The release rate from polyurethane‐coated granules was also reduced by alkyl side chains. However, it was faster than that through a plain membrane because of capsule expansion by continuous water penetration and structural changes in the membrane. CONCLUSION: The release rate of urea through a polyurethane plain membrane and from polyurethane‐coated granules can be controlled by changing the chemical properties of the membrane. In addition, physical properties such as the glass transition temperature T_g or crosslink density should be considered to assess the release profile from polyurethane‐coated granules. Copyright © 2009 Society of Chemical Industry