Development of new natural polymer-based wood adhesives III: effects of glucose addition on properties of chitosan

The effects of a Maillard reaction between glucose and chitosan on the resultant chitosan films and the bonding properties of chitosans with different molecular weights were investigated. In film preparation, chitosan and glucose were dissolved in 1% acetic acid and dried in a Petri dish at 50°C. The bonding properties of the Maillard-reacted chitosan in three-ply plywood were evaluated by a tensile shear test. The weight, color, free amino groups, insoluble fraction, and thermal properties of the film changed significantly as the amount of added glucose increased. However, few differences in these properties due to the use of chitosan of different molecular weights were observed. The effect of glucose addition on the tensile strength of the film differed for chitosans of different molecular weights. Improvement of the strength by 10 wt% glucose addition was observed in low-molecular-weight chitosans. The dry- and wet-bond strengths were significantly enhanced with increasing glucose addition for low-molecular-weight chitosans. In addition, good bond strength was maintained even in 1% acetic acid solution. It was thus clarified that the bonding properties of low-molecular-weight chitosan were improved markedly by the environmentally safe method of glucose addition.     

Effect of inorganic ions on bud cell formation by <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> in potato dextrose broth

Potato dextrose broth (PDB), a well-known medium for cultivation of fungi, can be made from potato extract and glucose (handmade PDB) or bought as a commercial powder (commercial PDB). Previously, we reported that bud cell formation and fungal biomass of Fusarium oxysporum in handmade PDB are higher than in commercial PDB, and the presence of high molecular weight (>20 MDa) carbohydrates in PDB promoted bud cell formation by most strains of F. oxysporum. In this study, we report the effects of inorganic ions in PDB on bud cell formation and fungal biomass production by F. oxysporum. Concentrations of Mg, K, Fe, PO₄ ³⁻ and SO₄ ²⁻ were higher and of Na and Cl⁻ were lower in handmade PDB than in commercial PDB. Adding each inorganic ion alone to commercial PDB showed that Mg is critical for enhancement of bud cell formation by some strains of F. oxysporum. The addition of Mg²⁺ with raw potato starch to commercial PDB promoted bud cell formation by some, but not all, of the seven F. oxysporum strains tested in this study.     

Experimental infection of calves with Pasteurella multocida Serovar A: 3 isolated in Japan

Pasteurella multocida, serovar A: 3, selected by pathogenicity in mice from among 10 strains isolated from pneumonic lesions of calves, was adjusted to 10(7), 10(8) and 10(10) colony-forming units (CFU), and inoculated intratracheally into four calves. All calves showed pyrexia and had lungs with congestion and hepatization. Inoculation with 10(10) CFU of bacteria produced respiratory symptoms and abscesses in lungs. This information will aid elucidation of the pathogenicity of P. multocida and the development of vaccines.     

Control of the collagen fibril diameter in the equine superficial digital flexor tendon in horses by decorin

The distribution pattern of collagen fibril diameter in the equine superficial digital flexor tendon (SDFT) is known to differ in central and peripheral areas of some regions. This study reports the essence of collagen fibril differences among different regions of the equine SDFT by transmission electron microscopic (TEM) and high-voltage electron microscopic observations and biochemical analysis. The distribution of large collagen fibrils increased but the density of collagen fibrils decreased from the proximal metacarpal region to the distal metacarpal region. Large collagen fibrils with an irregular cross-sectional profile were found more frequently in the middle metacarpal region than in other regions. Three-dimensional reconstruction of images of irregularly shaped collagen fibrils revealed that these fibrils are formed through fusion of small collagen fibrils with large ones. The amount of decorin, which reportedly inhibits the lateral fusion of collagen fibrils, decreased in the direction of the distal metacarpal region. On the other hand, the size of decorin gradually increased in the direction of the distal metacarpal region. These results suggest that regional differences in collagen fibril distribution and density of collagen fibrils in the SDFT are due, at least in part, to fusion of collagen fibrils and the concomitant regional differences in the amount and size of decorin.     

Urinary transforming growth factor-beta1 in feline chronic renal failure

Transforming growth factor-beta1 (TGF-beta1), an inflammatory cytokine, plays a role in tissue fibrosis, such as glomerular sclerosis and tubulointerstitial fibrosis of the kidneys. In the present study, the urinary TGF-beta1 level of cats diagnosed with chronic renal failure (CRF) was measured to investigate its relationship to the pathogenesis of feline CRF. Urinary TGF-beta1 levels (TGF-beta1/creatinine ratio) were significantly increased compared with healthy controls, whereas serum levels of TGF-beta1 were not. These results indicate that TGF-beta1 is expressed in the kidneys of CRF cats, and that it was reflected in the urinary TGF-beta1 level. Therefore, TGF-beta1 may play a role in feline CRF, and urinary TGF-beta1 could be used as a clinical marker for renal fibrosis.     

Distribution patterns of mulberry dwarf phytoplasma in reproductive organs,winter buds,and roots of mulberry trees

Distribution patterns of mulberry dwarf (MD) phytoplasma were investigated in several organs of dwarf-diseased mulberry trees using direct and nested polymerase chain reactions and electron microscopy. MD phytoplasma was detected in the root of all MD-diseased trees collected from overwintering to before sprouting in the cold district; however, it was not always found in winter buds of the same trees. On the other hand, MD phytoplasma was also detected frequently in reproductive organs, such as flowers (female and bisexual flowerets), fruits (catkins), and seed coats, from a single diseased tree, although the distribution patterns were not uniform. In addition, MD phytoplasma was verified to move into roots from ground plant organs after an artificial inoculation test using the leafhopper Hishimonoides sellatiformis as a vector.