Antigenic variation of Newcastle disease viruses isolated from wild ducks in Japan

Nineteen strains of Newcastle disease virus (NDV) isolated from wild ducks in Japan were placed into 4 distinct antigenic groups on the basis of their reactivities to 8 monoclonal antibodies against the HN molecule of NDV in hemagglutination inhibition tests. The NDV strains of duck origin were antigenically distinct from NDV-B1 and NDV-Miyadera originated from chickens, and varied in their virulence to chicken embryos. No apparent correlation was found between the antigenicity of the HN molecule and virulence.     

Effects of frequency of the tones on auditory event related potentials in monkeys (Macaca fuscata) under various hypobaric hypoxia conditions of simulated high altitudes

Changes in auditory event related potentials (ERPs) as a function of frequency of tones ranging from 500 Hz to 8,000 Hz were examined under various hypobaric hypoxia conditions of simulated high altitudes up to 6,000 m. A sequence of P₁-N₁-P₂ components, corresponding to those of the human subject, was observed with the monkey's ERPs. These component amplitudes changed as a function of frequency of tone. The relationship revealed an inverted U curve with a maximum amplitude at a tone of 2,000 Hz. The following results under hypoxia were noted: marked reduction of amplitude in ERPs induced by hypoxia linked only to a tone's particular frequency, especially for 2,000 Hz. The delay of latency in the respective components of the ERPs was dependent on the degree of hypoxia. These findings seem to suggest the anatomical bases of the neural generators contributing to each component of the ERPs. This work was supported by the Cooperation Research Program, Primate Research Institute, Kyoto University.     

Water structure in modified bovine plasma albumin (BPA) gel and bovine mercaptalbumin solution. 1H-n.m.r. studies

Bovine plasma albumin Fr. V (BPA) has been known to contain small amounts of proteolytic enzyme. Wilson & Foster (1971) found a very limited and specific cleavage of BPA catalyzed by the enzyme with BPA in the F-form near pH 3.8, resulting in the formation of partially hydrolyzed BPA (BPA*). BPA* had a tendency to form a transparent gel at pD 4.0 (pD range of the F-form) above 8%, though proteolytic enzyme-free bovine mercaptalbumin (BMA) was in a transparent solution at pD 4.0 even at 12%. Water structures of the F-form of BMA in the solution state and of BPA* in the gel state were studied by measuring 1H-n.m.r. spectra, spin-lattice relaxation time (T1) and cross relaxation time (TIS) between irradiated and observed protons. Protein concentration-dependent changes of T1 of water protons indicated that the amount of hydrated water of BPA* in the gel state is far greater than that of the F-form of BMA in the solution state. TIS values from protein protons to water protons also indicated a large amount of hydration of BPA*, strong interaction between water and BPA* and rapid exchange between bound and bulk water in the gel state.     

Establishment of hybridomas secreting human monoclonal antibodies against tetanus toxin and hepatitis B virus surface antigen

Mouse-human heterohybrids (M X H) were constructed and compared with other cell lines (human or mouse) as parental cells to obtain hybrids secreting human monoclonal antibody (MoAb). One of the M X H lines, HM-5, was far superior to the others and useful for establishing hybrids secreting human MoAb. Using HM-5 as a parental cell line, we have obtained 2 hybrids secreting human anti-tetanus toxoid MoAb with neutralizing activity and a hybrid secreting human anti-hepatitis B virus surface antigen (HBsAg) MoAb which recognizes the a-determinant of HBsAg.     

Filopodium-derived vesicles produced by MIM enhance the migration of recipient cells

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