Quantitative diversity of 67 kda protective antigen among serovar 2 strains of Erysipelothrix rhusiopathiae and its implication in protective immune response

Mouse monoclonal antibodies (MAbs), raised against the NaOH-extracted antigen of Erysipelothrix rhusiopathiae strain Kyoto (serovar 2), recognized two different epitopes on a single protein of molecular weight 67 kDa. The MAbs were classified as protective or non-protective against strain Fujisawa (serovar 1). In immunoblotting analysis using the MAbs, fifteen wild strains were shown to contain different amounts of 67 kDa protective antigen. Each formalin-killed whole cell vaccine (bacterin) prepared from the fifteen wild strains conferred different levels of protection against strain Fujisawa in mice. Bacterins prepared from wild strains with larger amounts of 67 kDa protective antigen tended to give high levels of antigen-specific antibody and better protection to mice. These results indicate that the amount of 67 kDa protective antigen which influences the induction of protective immune responses may vary substantially among the strains of E. rhusiopathiae (serovar 2).     

AN EVALUATION OF A NEW RADIOGRAPHIC TECHNIQUE UTILIZING A CONCAVE TABLE

In conventional radiography systems, it is apparent that only the area immediately around the central x-ray beam can be evaluated accurately. Consequently in some instances, spinal radiography for example, several exposures are needed at various points along the body to create an accurate image for diagnosis. However, if the film and body part are in a concave shape such that the radius of the curve is equal to the film focal distance, the x-ray beam will penetrate the body and strike the film at two-dimensionally right angles in all areas. Using the spine as an example we found the curved technique had three major advantages over the traditional flat technique: lack of distortion, more uniform beam intensity due to a constant focal film distance, and improved resolution at the periphery of the radiograph because of lack of a cross over effect. It was concluded that an accurate evaluation of larger body parts can be made with minimal distortion utilizing the principles of a curved table technique.     

Genetic selection for resistance to mycoplasmal pneumonia of swine (MPS) in the Landrace line influences the expression of soluble factors in blood after MPS vaccine sensitization

We recently developed a Landrace line that is resistant to mycoplasmal pneumonia of swine (MPS) infection by genetic selection for five generations, and we reported that the immunophenotype of this line is different from that of the non‐selected line in terms of changes in peripheral blood leukocyte population after MPS vaccination. This study followed up previous findings demonstrating changes in soluble factors in blood, namely, hormones, Mycoplasma hyopneumoniae‐specific immunoglobulin G (IgG), and cytokines. These two lines were injected with MPS vaccine on days ?7 and 0 after blood sampling on those days, and blood samples were collected on days ?14, ?7, 0, 2, 7 and 14. We found changes in the levels of many hormones and cytokines in both lines. However, we found that only growth hormone (GH) and interferon (IFN)‐γ levels were statistically different between these two lines. GH concentration was reduced (day 0) and IFN‐γ concentration was increased (day 14) in the MPS‐selected line compared with the non‐selected line, despite unchanged IFN‐γ messenger RNA expression in blood cells. Although detailed mechanisms underlying these phenotypes remain unsolved, these traits would be useful to improve MPS resistance in pig production and provide an insight into MPS infection.     

Macroscopic separation of dense fluid phase and liquid phase of phosphorus

Structural transformation between a dense molecular fluid and a polymeric liquid of phosphorus that occurred at about 1 gigapascal and 1000 degrees C was investigated by in situ x-ray radiography. When the low-pressure fluid was compressed, dark and round objects appeared in the radiograph. X-ray diffraction measurements confirmed that these objects were the highpressure liquid. The drops grew and eventually filled the sample space. Decompressing caused the reverse process. The macroscopic phase separation supported the existence of a first-order phase transition between two stable disordered phases besides the liquid-gas transition. X-ray absorption measurements revealed that the change in density at the transition corresponds to about 40% of the density of the high-pressure liquid.     

Pear (Pyrus Species) Genetic Resources in Iwate, Japan

Iwateyamanashi (Pyrus ussuriensis Maxim. var. aromatica (Nakai et Kikuchi) Rehd.) is one of the Pyrus species grown wild in Japan. The origin of the Japanese pear (P. pyrifolia) is uncertain but it has been suggested that Iwateyamanashi is the possible progenitor of the modern Japanese cultivar. During the last few decades, the number of Iwateyamanashi trees has been decreasing and therefore, conservation is urgently needed. After 13 explorations in the northern Tohoku region of Japan, 615 pear trees and 30 local names were recognized mainly in Iwate Prefecture. The center of the distribution seemed to be somewhere around Mt. Hayachine to the northern area of Kitakami highlands (from lat. 39 °20′ to 40 °10′N, and from long. 141 °20′ to 141 °50′E). Four morphological characters concerning fruit shape, measured for 85 trees, showed a wide range of continuous variation. For the skin colour of fruit, 51% of trees bore russet type fruits, 22% smooth and 27% intermediate ones. Most of the fruits had five loculi but Sanenashi fruits (seedless pear), one of the old cultivars, had three, and fruits of another two trees had four. More than 80% of trees tended to produce fruits with a calyx but some trees bore fruits without a calyx. These observations indicate a wide range of genetic diversity in Pyrus species which is caused, not only by high heterogeneity in Iwateyamanashi itself, but also by the coexistence of Iwateyamanashi, P. pyrifolia (Burm.) Nakai and hybrid progeny in this area. Already 250 trees have been conserved as genetic resources by grafting at Kobe University.     

Application of activable tracers to investigate radial movement of minerals in the stem of Japanese cedar (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>)

Two activable tracers, Rb and Eu, were injected into the sapwood of Japanese cedars (Cryptomeria japonica D. Don) to investigate the radial movement of minerals in their stems in the resting period. Eight trees of four cultivars, two of which genetically form wet heartwood, were treated near the end of the growing period. At 40 days after the treatment, Rb was detected in the outer heartwood, whereas Eu was not. Radial movement of Rb was more rapid in trees with wet heartwood than in those with normal heartwood. At 204 days after the treatment, more Rb was detected in the heartwood than was found on the first sampling, whereas no Eu was detected in the heartwood. The difference in radial movement between Rb and Eu was considered mainly to be the result of selective transport of beneficial minerals by Japanese cedar. The difference in the rate of radial movement of Rb between wet and normal heartwood became more conspicuous at 204 days after treatment. We concluded that the movement of Rb from the sapwood to the outer heartwood was by active transport through the rays, whereas that in the heartwood was by diffusion due to the gradient of Rb concentration.     

Inheritance of low pasting temperature in sweetpotato starch and the dosage effect of wild-type alleles

Sweetpotato (Ipomoea batatas (L.) Lam.), which is an outcrossing hexaploid, is one of the most important starch-producing crops in the world. During the last decade, new sweetpotato cultivars, e.g. ‘Quick Sweet’, which have approximately 20°C lower pasting temperature, slower retrogradation and higher digestibility of raw starch than ordinary cultivars, have been developed in Japan. Genetic analysis of these variants with low pasting temperature starch was conducted in this study. Using 8 variants and 15 normal clones, 26 families were generated. The results from analyzing these progenies suggested that this trait is a qualitative character controlled by one recessive allele (designated spt), which is inherited in a hexasomic manner. A dosage effect of the wild-type Spt allele was found for starch pasting temperature, although the effect was not linear. These results will aid breeders to develop sweetpotato cultivars with a range of starch pasting temperatures.     

Postnatal development of hypoplastic thymus in semi-lethal dwarf pet/pet males

The petit rat (pet/pet) is a new semi-lethal dwarf mutant with anomalies in the thymus and testes, defects inherited as a single autosomal recessive trait. At birth, these pet/pet rats show low birth weight and extremely small thymuses; at 140 days of age, their thymuses show abnormal involution. In the present study, we examined early postnatal development of hypoplastic pet/pet thymuses. In addition to being hypoplastic at birth, pet/pet thymus growth was almost completely impaired during the early postnatal period. As shown by cellular incorporation of BrdU, the mitotic activity was lower in pet/pet than in normal thymuses, and terminal deoxynucleotidyl transferase dUTP nick end labeling assays showed that apoptosis occurred more often in pet/pet than in normal thymus cells during the first few days after birth. These results indicate that postnatal development of the hypoplastic pet/pet thymus is defective due to the reduced proliferation and increased apoptosis of thymic cells.