Hog Cholera: I. Investigation of the Agar Double-Diffusion Precipitation Test for The Detection of the Virus in Swine Tissue

The agar double-diffusion precipitation test was investigated to detect hog cholera virus in splenic and pancreatic tissues of swine. Special attention was given to the conditions influencing the sensitivity and specificity of the test. These studies emphasize the strict techniques and methods required in the test in order to detect specific antigen — antibody reaction. Absorption studies performed on serum fractions prepared by DEAE cellulose chromatography and studied electrophoretically, indicated the specific reaction was given by fractions, migrating in the gamma-globulin region and was absorbed by infected but not by normal spleens. The sensitivity of the test is dependent to a great extent on the successful liberation of the viral antigen from the tissue.     

Effects of alpha-pinene odor in different concentrations on stress-induced hyperthermia in rats

Stress-induced hyperthermia is observed in animals exposed to stressful conditions. In our previous study, plant-derived fragrances such as green odor and alpha-pinene were shown to suppress this stress response in rats. In the present study, we examined the concentration-dependence of the alpha-pinene effects on stress-induced hyperthermia. Male rats carrying telemetry transmitters were transferred individually to a new cage containing bedding that had been sprayed with 0.3, 0.03, and 0.003% concentrations of alpha-pinene or control solvent. Following transfer to the novel environment, the body temperature increased significantly, and this response was clearly suppressed when the cage was scattered with 0.03% alpha-pinene only. These results suggest that the effect of alpha-pinene on stress-induced hyperthermia can be observed only at a certain concentration.     

Substances derived from 4-ethyl octanoic acid account for primer pheromone activity for the "male effect" in goats

A major constituent of the characteristic "goaty odor" 4-ethyl octanoic acid (4EOA) was previously shown to have no primer pheromone activity. This was also confirmed by our own bioassay system utilizing the recording technique of neural activity of the hypothalamic gonadotropin-releasing hormone pulse generator in goats. However, when the synthetic 4EOA solution was kept at room temperature for several months, primer pheromone activity appeared in the same solution. Headspace gas chromatography/mass spectrometry analysis revealed that there were several newly formed substances in addition to 4EOA samples with primer pheromone activity. These results suggest that 4EOA derived substance(s) but not 4EOA itself is(are) primer pheromone in goats.     

Hyaluronidase is not essential for the lethality of Erysipelothrix rhusiopathiae infection in mice

To investigate the role of hyaluronidase in the pathogenicity of Erysipelothrix rhusiopathiae, transposon Tn916 was transferred from Enterococcus faecalis CG110 to a virulent strain of E. rhusiopathiae, and hyaluronidase-deficient mutants were isolated. A virulence assay in the mice showed that of the seven hyaluronidase-deficient mutants tested, six mutants were avirulent, but that one mutant, designated AST121, was as virulent as its parental strain. Western immunoblotting with a monoclonal antibody specific to the capsule, a major virulence factor of the organism, revealed that all of the avirulent mutants had lost the capsular antigen, whereas the mutant AST121 did not. These results suggest that the lack of virulence of the six hyaluronidase-negative mutants could be due to a loss of the capsule and that hyaluronidase does not contribute to the lethality of E. rhusiopathiae infection in mice.     

Interaction of dinotefuran and its analogues with nicotinic acetylcholine receptors of cockroach nerve cords

To investigate the action of dinotefuran (MTI-446, 1-methyl-2-nitro-3-(tetrahydro-3-furylmethyl)guanidine), a recently developed insecticide, on insect nicotinic acetylcholine receptors (nAChRs), we determined the potencies of the compound and 15 analogues in inhibiting the specific binding of [3H]epibatidine (EPI), a nAChR agonist, and [3H]alpha-bungarotoxin (alpha-BGT), a competitive nAChR antagonist, to the nerve cord membranes of American cockroaches (Periplaneta americana). Racemic dinotefuran inhibited [3H]EPI binding with an IC50 of 890 nM and [3H]alpha-BGT binding with an IC50 of 36.1 microM. Scatchard analysis indicated that the dinotefuran inhibition of [3H]EPI binding was a competitive one. Slight structural modification caused a drastic reduction in potency; only four analogues were found to be equipotent to or more potent than dinotefuran. Chloropyridinyl and chlorothiazolyl neonicotinoid insecticides displayed two or three orders of magnitude higher potency than dinotefuran. There was a good correlation between the IC50 values of tested compounds obtained with [3H]EPI and those obtained with [3H]alpha-BGT. A better correlation was observed between 3-h knockdown activities (KD50) against German cockroaches (Blattella germanica) and IC50 values obtained from [3H]EPI assays than between 24-h lethal activities (LD50) and IC50 values. While the results indicate that dinotefuran and its analogues interact with the ACh-binding site in cockroach nAChRs, it remains to be elucidated why they displayed lower potencies than those expected based on their insecticidal activities.     

Novel species specific antigens of trypanosoma congolense and their different localization among life-cycle stages

Seven monoclonal antibodies (mAbs) were raised against Trypanosoma congolense procyclic form (PCF). Localization of the antigens recognized by the mAbs was determined in bloodstream form (BSF), PCF, epimastigote form (EMF) and metacyclic form (MCF) by confocal laser scanning microscopy (CLSM). Two mAbs (10F9 and 20H12) showed different fluorescent patterns among different life-cycle stages of the parasite. The 10F9 recognized a 76 kDa antigen of all life-cycle stages of the parasite and the antigen localization corresponded with that of a mitochondrion. While the 20H12 recognized 119 and 122 kDa antigens of all the life-cycle stages and the antigen localization corresponded with a flagellum in BSF and MCF, tip of a flagellum in PCF, and part of cytoplasm in EMF. Moreover, the 20H12 did not react to T. brucei gambiense, T. b. rhodesiense and T. evansi antigens in both CLSM and immunoblotting. Therefore, the antigens recognized by the 20H12 seem to be T. congolense specific. Although, further studies will be required for a full characterization of the T. congolense specific 119 and 122 kDa antigens, the mAb 20H12 and the specific antigens may be useful in not only establishment of T. congolense specific diagnosis methods but also studies on molecular mechanisms regulating differentiation of the parasite during life-cycle.     

Regional differences of pheromone production in the sebaceous glands of castrated goats treated with testosterone

The primer pheromone is responsible for the "male effects" in goats and produced in the sebaceous glands testosterone-dependently. In the present study, the responses of sebaceous glands obtained from the head and rump regions of castrated goats were examined by our bioassay system after testosterone treatment to demonstrate the presence of regional differences in the pheromone production in male goats. The testosterone treatment resulted in the marked development of sebaceous glands and the induction of pheromone bioactivity in the head region of the goats. On the contrary, this treatment brought neither development of the sebaceous glands nor induction of pheromone bioactivity in the rump region. The treatment increased immunoreactivities to androgen receptors (AR) and 5alpha-reductase in the sebaceous glands of both regions, although the activities were more apparent in the head region than the rump region. These findings suggest that the primer pheromone of male goats is produced specifically in the sebaceous glands of the head region due partly to regional differences in the expression of AR and 5alpha-reductase mediating testosterone bioactivities.     

Effect of liquid paraffin on antibody responses and local adverse reactions of bivalent oil adjuvanted vaccines containing newcastle disease virus and infectious bronchitis virus

Effects of liquid paraffin on antibody responses and local adverse reactions after intramuscular injection of oil adjuvanted vaccines containing Newcastle disease (ND) and infectious bronchitis (IB) virus were investigated in chickens. Each vaccine was prepared with a liquid paraffin such as Carnation, Crystol 52 and Lytol. These vaccines induced sustained antibody responses against ND and IB. Among local adverse reactions, Lytol induced granulomatous reactions and abscesses, but Carnation and Crystol 52 did not. The residual weight of liquid paraffin at the injection site decreased in the order Carnation, Crystol 52, Lytol. Crystol 52 was composed of relatively few short-chain hydrocarbons (i.e., n-C20H42). The vaccine with liquid paraffin mainly composed of n-C16H34-n-C20H42 was suggested to induce fewer adverse reactions.     

Long-term growth analyses of Japanese cedar trees in a plantation: neighborhood competition and persistence of initial growth deviations

The individual growth of tree diameter at breast height (dbh) is analyzed in an even-aged plantation of Cryptomeria japonica from stand age of 45 to 94 years, to examine how the growth of individual trees has been affected by the changes in spacing resulting from thinning operations. At any age, a significant proportion (0.37–0.46) of the variation in dbh growth during a 5–11-year period was explained by dbh at the beginning of the period, probably due to greater leaf mass of larger trees. Next, either one-sided or two-sided competition was added to the model, by calculating the basal area (BA) of neighboring trees around each tree within a given radius or BA for trees having larger dbh than the focal tree within the radius. After preliminary analyses, a radius of 8 m was selected as the critical range for tree competition. Although both types of competition explained a significant proportion (0.09–0.43) of growth variation, one-sided competition was not significant at ages greater than 54 years. Based on the model at 45 years of age, the initial deviation of growth rate for each tree from the predicted rate was calculated and added to the models as a third variable. This raised the coefficient of determination up to 0.50–0.74. These findings have practical significance for forest plantation management, particularly for controlling the growth of standing trees via thinning, to produce high-quality timber in the future.