Yu Zengliang

Transferring Gus gene into intact rice cells by low energy ion beam

Abstract A new technique of transferring genes by low energy ion beam has been reported in this paper. The Gus and CAT (chloramphenicol acetyltransferase) genes, as “foreign” genetic materials, were introduced into the suspension cells and ripe embryos or rice by implantation of 20–30 keV Ar + at doses ranging from 1 × 10 15 to 4 × 10 15 ions/cm 2 . The activities of CAT and Gus were detected in the cells and embryos after several weeks. The results indicate that the transfer was a success.

Dose-effect of the tyrosine sample implanted by a low energy N+ ion beam

Abstract It has been found that the sample of tyrosine implanted by a low energy N + ion beam had a special dose-effect that was different from traditional theory. A mathematical equation of this special regulation was deduced; it reflected the importance of depositing of the slowed-down ions. In this paper, the interaction between the implantation N + with the tyrosine molecules was also analyzed.

Mass deposition in tyrosine irradiated by a N+ ion

Abstract Based on the measured UV-, IR-, laser-Raman, and mass spectra, and analyzed with the quantum theory, the reaction pattern of an implanted N + ion with tyrosine molecule (Tyr) was deduced. It was found that a substitute reaction of the slow down N + with the group C(5)H- of Tyrs benzene ring had taken place. In addition, a new carbonyl group was measured in the irradiated Tyr sample. Hence, a N-heterocyclic compound was formed.

Study on the Effect of Mutated Bacillus Megaterium in Two-Stage Fermentation of Vitamin C

Bacillus megaterium as a companion strain in two-stage fermentation of vitamin C could secrete some active substances to spur growth of Gluconobacter oxydans to produce 2-KLG. In the fermenting system where Gluconobacter oxydans was combined with GB82-a mutated strain of B. megaterium by ion implantation, the amount of 2-KLG harvested was larger than that produced by the original B. megaterium BP52 [1] being substituted for GB82. In this paper, we studied the effect of the active substances secreted by GB82 to enhance the capability of Gluconobacter oxydans to produce 2-KLG. The supernate of GB82 sampled at different cultivation times all had much more activity to spur Gluconobacter oxydans to yield 2-KLG than that of the original B. megaterium, which might be due to the genetic changes in the active components caused by ion implantation. Furthermore, the active substances of GB82s supernate would lose a part of its activity in extreme environments, which is typical of some proteins.

Repair by radiation itself or not? A study of threonine irradiated by keV ion

Abstract A saddle type dose-survival rate curve of threonine was confirmed in low energy ion irradiation. Mass spectrometry has been used as an analytical tool in determining the species and quantities of volatile reaction products generated during the decomposition of threonine by fast atom bombardment. The radiation chemistry was related to the radiation physics of fundamental interaction between the projectile and target molecule. The nuclear collision process was proposed as the main reason of the particular dose effects curve, based on the analysis of the interaction process between the projectile and target molecule. A new repair model was assumed.

Research into releasing inorganic phosphate and base from 5′-dTMP irradiated by a low energy ion beam

Abstract Research into radiation damage of nucleotide is an important area in radiation biology. In this paper, the yield of inorganic phosphate and base released from 5′-dTMP irradiated by a 30 keV N + ion beam was investigated in several aspects. The effect of particle fluence on yield and the influence of treatment with 0.1 N NaOH was deduced. By analysis, it is known that the alkali treatment not only increases the yield of inorganic phosphate, but also damages and splits the base released from irradiated 5′-dTMP. When the irradiated samples are treated by 0.1 N NaOH immediately, the yield of inorganic phosphate is increased by a factor of 1.7 and the concentration of base decreased to half of the original value. But the yield of inorganic phosphate could be increased by a factor of 2.8 after 40 min of alkali treatment. On the other hand, when 5prime;-dTMP was irradiated by the ion beam, the G(Pi) obtained was above 0.44, higher than with γ-radiation.

keV ion irradiation of solid glycine: an EPR study

Abstract The radicals formed in keV ion irradiation of solid glycine were studied using electron parameter resonance (EPR). Spectra were observed at different temperature from 100 to 310 K after irradiation at room temperature. Different radicals are formed in different radiation conditions. The structure and concentration of the main radicals formed under 30 keV ion irradiation remain stable in different measurement temperature and radicals formed under 20 keV ion irradiation vary. The results indicate that more kinds of radicals are formed under keV ion irradiation which is attribute to the nuclear collision process. It is in agreement with previous study with mass spectrometer.

Comparison of base substitutions in response to nitrogen ion implantation and 60Co-gamma ray irradiation in Escherichia coli

To identify the specificity of base substitutions, a novel experimental system was established based on rifampicin-resistant (Rifr) mutant screening and sequencing of the defined region of the rpoB gene in E. coli. We focused on comparing mutational spectra of base substitutions induced by either low energy nitrogen ion beam implantation or 60Co-gamma rays. The most significant difference in the frequency of specific kinds of mutations induced by low energy nitrogen ion beam was that CG ®TA transitions were significantly increased from 32 to 46, AT ®TA transversions were doubled from 7 to 15 in 50 mutants, respectively. The preferential base substitutions induced by nitrogen ion beam implantation were CG ®TA transitions, AT ®GC transitions, AT ®TA transversions, which account for 92.13% (82/89) of the total. The mutations induced by 60Co-gamma rays were preferentially GC ®AT and AT ®GC transitions, which totaled 84.31% (43/51).

Synthesis of amino acids by arc-discharge experiments

Abstract Discharge was performed against ammonia water using a graphite rod as the anode and a silver thread as the cathode under an Ar atmosphere. HPLC and thin layer chromatograph (TLC) analyses showed that three kinds of amino acids were produced in the reaction mixture. As the graphite anode is the solitary source of carbon in the system, it is considered that amino acids have been produced by synthetic reaction between graphite and ammonia water. Thus, our results provide a possible way of formation of amino acids from elemental carbon on the primitive earth. In addition, the mechanism for the production of amino acids is discussed and the yields of different amino acids are presented.

Phosphate release from N+ ions irradiated 5'-CMP nucleotide and its kinetics

Abstract Ion beam irradiation-induced inorganic phosphate (Pi) release from 5′-CMP nucleotide could be divided into two parts: fast process and slow process. The yield of Pi released from the fast process not only had a non-linear response to irradiation dose, but was also influenced by post-irradiation treatments. It was found that heat treatment and alkali treatment increased the yield of Pi but acid treatment decreased it. With the heat treatment lower than 80°C, the Pi release process followed the first order reaction model, but under the conditions of 95°C treatment and alkali treatment the Pi release process followed the second order reaction model. Moreover, the kinetics equations and the rate constants of different models of the Pi release reactions were deduced.