Improvement of the Half-embryo Test for Detection of Gamma-irradiated Grapefruit and Its Application to Irradiated Oranges and Lemons

The duration of the half-embryo test used for identification of gamma-irradiated grapefruit was shortened by increasing germination temperature to 35°C. Maximum shooting percentages were reached within 3 days. Gibberellin application reduced the required incubation time to 2 days. Half-embryos extracted from irradiated orange and lemon gave similar results to those of grapefruit. This half-embryo test is proposed as an identification method for irradiated citrus. Assessment can be made after 3 to 4 days when shooting percentage is greater than 50%.     

A Half-Embryo Test for Identification of Gamma-Irradiated Grapefruit

Whole grapefruit were exposed to 5, 15, 30, 50, and 100 krad doses of gamma-radiation. Seeds were removed and half-embryos, consisting of one cotyledon and embryo axis, dissected from the surrounding tissue. Nonirradiated half-embryos germinated faster than intact or partially dissected (outer seed coat removed) seeds. Shoot elongation was also quicker, occurring within 6 days. Irradiated half-embryos over 15 krad doses showed markedly reduced root growth and shoot elongation was almost totally retarded. Differences between irradiated and nonirradiated half-embryo were not affected when variety, harvest date, and fruit storage conditions were varied. This test could thus discriminate between irradiated and non irradiated grapefruit.     

Training and Research on Photovoltaic at HNCT

Translated from the Japanese     

Complex Permittivity Spectra of Various Insulating Polymers at Ultrawide‐Band Frequencies

Nowadays, trials to use even higher frequencies are pursued to realize high‐speed wireless communications. In order to respond to such a trend, dielectric properties of insulating polymers at high frequencies have to be clarified, although the importance of clarifying low‐frequency properties is still very high, especially for use as high‐voltage insulators. In this regard, complex permittivity spectra from 10 mHz to 4.0 THz were obtained for various insulating polymers. The spectra obtained in the very wide frequency range are important, because they can be a valuable database and they provide various pieces of important information on dielectric characteristics.     

STABILITY OF STRONTIUM(II) AND BARIOM(II) COMPLEXES WITH 18-CROWN-6 IN AQUEOUS SOLUTION AND THEIR EXTRACTABILITY AS PICRATES

When strontium(II) and barium(II) were extracted with 18-crown-6(l 8C6) and picrate ions into chloroform, log(distribution ratio of metal(II)) approached flat in a higher region of log[18C6], although it is reported that the distribution ratio of copper(II) or zinc(II) increases in proportion to the second order of 118C6]. From the extraction data analysis, the flat distribution ratio was explained by the formation of the aqueous complex with 18C6 and the stability constants for strontium(II) and barium(II) were determined to be 2.89 and 3.68 as logβ1respectively.     

Drift of amplification factor and its effects in a tri-electrode electron gun†

The drift of the amplification factor p. should induce drifts of the emitted current I a in a fixed-bias circuit and the beam energy in a self-bias circuit.

The μ-drift due to the heat from the filament was measured, and also calculated from the I _A-drift for an hour. The relative μ-drift thus calculated was 1-3% in 10?min in a conventional gun, and it decreased to smaller than 003% in 10?min in an improved gun, where thermal expansion of the Wehnelt electrode was compensated by the movement of the filament supporter. Energy of the beam was 20 kev. The initial emitted current I _A(t= 0) was 198 μA in the conventional gun and 14.4 μA in the improved gun.

The relative energy-drift should be proportional to the relative μ-drift and inversely proportional to (μ+ 1). Accordingly, the relative energy-drift should be 1.3 × 10^?6; in 10?min in the conventional gun, while it should be smaller than 3 ×10^?6 in 10?min in the improved gun, when μ is assumed to be 100 in both guns.     

Sensory Changes in Umami Taste of Inosine 5'-Monophosphate Solution after Heating

Discrimination in umami taste of inosine 5′-monophosphate (IMP) solution caused by thermal degradation was investigated by sensory evaluation. The difference threshold of umami taste of 0.005% IMP solution in the presence of 0.05% monosodium glutamate (MSG) was 0.002%. The difference threshold of a 0.005% IMP solution decreased by about one half when heated at 95°C for 15 h. Inosine, one of the main products of the thermal degradation of IMP, had a bitter taste. The detection threshold of inosine varied widely among panelists. Heating a 0.005% IMP solution at 95°C for 15 h formed inosine at about one tenth of its lowest detection threshold.     

EFFECT OF MICROBIAL GROWTH UPON SARCOPLASMIC AND UREA-SOLUBLE PROTEINS FROM MUSCLE

SUMMARY– A comparison of starch gel patterns of sarcoplasmic proteins from aseptic and inoculated porcine and rabbit muscles after storage for 0, 8 and 20 days at 10°C indicated that different microorganisms preferentially utilized specific proteins. Pseudomonas fragi showed the greatest amount of proteolytic activity upon the sarcoplasmic fraction, causing extensive breakdown in both rabbit and porcine muscle. Leuconostoc mesenteroides caused extensive alteration in the sarcoplasmic proteins of rabbit muscle, but had less effect upon porcine muscle. Pediococcus cerevisiae exhibited similar action to L. mesenteroides upon rabbit muscle sarcoplasmic proteins, but had no effect upon pig muscle. Micrococcus luteus showed only minor breakdown of rabbit muscle sarcoplasmic proteins, and had no action upon porcine muscle. Both P. fragi and P. cerevisiae caused considerable breakdown of the urea-soluble proteins in pig muscle and to a lesser extent in rabbit muscle. Neither M. luteus nor L. mesenteroides exerted any measurable proteolytic effect upon the urea-soluble proteins. Possible implications concerning meat spoilage are discussed.     

The Isolation and Characterization of an a,4 (4,5 Dehydrogalacturonosyl) Galacturonate Hydrolase

SUMMARY– An unsaturated oligogalacturonate hydrolase was isolated from the cell extracts of a Bacillus sp. This enzyme attacked only the a 1,4 glycosidic bond adjacent to the terminal 4,5dehydrogalacturonate of unsaturated oligogalacturonides and preferentially attacked short chain unsaturated uronides. The rate of activity was maximal with unsaturated dimer followed by trimer (65% that of dimer), tetramer (47%) and pentamer (35%). The pH optimum was 6.3 to 6.6 and the enzyme did not require calcium ions for its activity. The enzyme was relatively stable below 30°C but lost 90% of its activity after 10 min at 40°C.