II. The effect of various doses of gamma 60Co radiation upon some morphological features of China aster (Callistephus chinesis Nees) in M1 and M2 generations

The present paper discusses the effect of antecedent gamma radiation upon 4 varieties of China aster in M₁ and M₂ generations. Studies were undertaken on the effect of various doses of radiation upon the following features : height of plants, maximal length of ramification of the Ist order, diameter of inflorescence, and number of set inflorescence. In M₁ generation (plants from irradiated seeds) negative effect of radiation was noted in almost all features under study, usually the greater the radiation dose. Only in case of two varieties ('Agnieszka' and 'Goplana') positive effect of irradiation upon plant height was noted, at radiation dose of 3 kR. However, further increase of radiation dose was harmful also for these two varieties. In M₂ generation (progeny of irradiated plants) the effect of gamma radiation upon most features under study was beneficial - in most cases stimulation overbalanced rare symptoms of depression. Reaction was different in all varieties under study.

Effects of Gamma Irradiation on the Viability and Phenotypic Characteristics of Salmonella Enteritidis Inoculated into Specific-Pathogen-Free Eggs

The goal of this study was to determine the effects of various levels of gamma irradiation on the phenotypic characteristics of 20 strains of Salmonella Enteritidis inoculated separately into specific-pathogen-free shell eggs. Bacterial strains were inoculated into egg yolks and exposed to 60Co radiation at doses of 0.49 to 5.0 kGy. The eggs were maintained at 25°C and analyzed for the presence of Salmonella on days 1, 2, 4, and 7, and the recovered Salmonella isolates were characterized biochemically. All strains were resistant to doses of 0.49, 0.54, 0.59, 0.8, and 1 kGy; colony counts were ≥105 CFU/ml of egg yolk except for one strain, which was detected at 96 h and at 7 days after irradiation at 1 kGy, with a population reduction of 2 log CFU/ml. For the other evaluated doses, 12 strains (60.0%) were resistant at 1.5 kGy and 7 strains (35.0%) were resistant at 3.0 kGy. Among all analyzed strains, 5.0 kGy was more effective for reducing and/or eliminating the inoculated bacteria; only two (10%) strains were resistant to this level of irradiation. Salmonella colony counts were significantly reduced (P < 0.01) with increasing doses from the day 1 to 7 of observation, when microbial growth peaked. Loss of mobility, lactose fermentation, citrate utilization, and hydrogen sulfide production occurred in some strains after irradiation independent of dose and postirradiation storage time. Increases in antibiotic susceptibility also occurred: seven strains became sensitive to β-lactams, two strains became sensitive to antifolates, and one strain each became sensitive to fluoroquinolone, phenicol, nitrofurans, tetracyclines, and aminoglycosides. The results indicate that up to 5.0 kGy of radiation applied to shell eggs inoculated with Salmonella Enteritidis at 4 log CFU per egg is not sufficient for complete elimination of this pathogen from this food matrix.

Functional Finishing on Silk Fabric with Acrylamide Monomer and Chitosan

The silk fabric was grafted with acrylamide monomer by the radiation of 60Co- ray and subsequently treated with the chitosan solution in aqueous citric acid. The effects of radiation dose, acrylamide monomer concentration and pH value on the grafting yield were investigated, respectively, and the maximum grafting yield was about 14% (w/w). Scanning electron microscopy photographs indicated that the surface of silk fabric was changed after acrylamide monomer and chitosan treatment. Infrared spectra analysis showed that the acrylamide monomer grafted into silk fabric after the 60Co- radiation, furthermore the chitosan combined with silk fabric through the esterifying reaction between citric acid and silk fiber. The crystallinity of the silk fiber grafted with acrylamide monomer enhanced by the analysis of X-ray diffractograms. With the acrylamide monomer grafting after the 60Co- radiation and the chitosan solution in citric acid treating, the wrinkle recovery angle of the treated silk fabric increased about 34.4% than the untreated silk fabric, the breaking strength percentage of the treated silk fabric decreased slightly. Meanwhile, the ratios of both anti-E.coli and anti-Stap.aureus for silk fabric treated by chitosan were over 93%, and the ratio of anti-C.albicans for silk fabric after chitosan treatment was about 77.6%. The properties of anti-wrinkle and anti-bacterium on silk fabric after the above functional finishing increase significantly, which is very helpful for the health of human beings.