The structure and amphipathy characteristics of modified γ-zeins by SDS or alkali in conjunction with heating treatment.

γ-Zein was modified by SDS or alkali combined with heating treatments in water and in 70% ethanol to change its amphipathic properties and explore the relationship between amphipathic characteristic and structure. γ-Zein water-dispersibility was dramatically increased via alkali or SDS combined with heating treatments, but their ethanol-dispersibilities were significantly different during ethanol evaporation. High both water-dispersibility and ethanol-dispersibility were found from alkali modified γ-zein while high water-dispersibility but low ethanol-dispersibility were obtained from SDS modified γ-zein, indicating that alkali modified γ-zein had better amphipathic characteristic compared with SDS modified γ-zein. Alkali modified γ-zein with higher amphipathic characteristic possessed higher structural inversion ability since it was easy to recover its native state as solvent changing from water to ethanol, contrary to SDS modified γ-zeins whose amphipathic characteristic was not improved. Moreover, the higher structural inversion ability of alkali modified γ-zein depended on the recovery capability of α-helix structure as solvent altering.

[Constituents of Dendrobium devonianum and their antioxidant activity].

OBJECTIVE: To study the chemical constituents of Dendrobium devonianum and identify the material basis components of its function, and then provide the basis for development and utilization of D. devonianum. METHOD: The constituents were separated and purified on the chromatography of silica gel, Sephadex LH-20 and RP-18 silica gel, and then their structures were elucidated based on the spectra data. ABTS method was used to evaluate the free radical scavenging activity of the phenolic compounds among them. RESULT: Nine compounds were isolated and identified as 2,3,4,9-tetrahydro-1H-pyrido[3,4-b] indole-3-carboxylic acid (1), 2'-deoxythymidine (2), adenosine (3), N-trans-p-coumaroyl tyramine (4), N-trans-p-feruloyl tyramine (5), 3-methoxy-4-hydroxybenzaldehyde (6), 4-hydroxybenzaldehyde (7), 3,4-dihydroxybenzoic acid methyl ester (8), and 4-hydroxy-3,5-dimethoxybenzoic acid (9). Compound 5 showed good antioxidant activity with IC50 1. 61 mmol. L-1, Compound 9 showed weak antioxidant activity with IC50 35.72 mmol. L-1. CONCLUSION: All these compounds were isolated from D. devonianum for the first time. Among them, compounds 5 and 9 had some antioxidant activity.

[Study on intraspecific genetic diversity in different plant populations of Pogostemon cabli].

OBJECTIVE: To study the genetic polymorphism and intraspecific genetic differentiation of different populations of Pogostemon cablin, and find out the effective method to distinguish DNA fingerprint of different populations of P. cablin. METHOD: Five plant populations of P. cablin were analyzed by RAPD markers. PopGen 32 software for clustering analysis and calculating. Fourteen of the 80 random primers were tested to possess the stronger detecting effect of polymorphous character. RESULT: A total of 84 bands was amplified by the 10 primers, among them 17 bands were monomorphic. 67 of them were polymorphic. The results indicated that the genetic variations existed within the different plant populations of the same species. CONCLUSION: It is feasible by RAPD technique with specifically primer to analyze the genetic diversity and identify 5 plant populations of P. cablin. RAPD technique has provided a new path for identification and classification of P. cablin genetic germplasm.

[In vitro culture and the Agrobacterium-mediated genetic transformation of Morinda officinalis].

OBJECTIVE: To establish an effective system for the Agrobacterium-mediated genetic transformation of M. officinalis, for laying a foundation for the improvement of breeds and introduction of foreign objective genes. METHOD: The explants used for culture were the nodular stem segments from M. officinalis. Agrobacterium tumefaciens strain was EHA101, containing vector plasmid pGA482GG. The GUS gene and NPT II gene were introduced into the plasmid. RESULT: MT basal medium with BA 1 mg.L-1 was effective to inducing the direct shoot formation, and the frequency of shoot formation was 97.8%. As BA concentrations increased, the ability of shoot formation decreased. The explants oriented with their apical ends protruding from the medium produced more shoots than when they were placed with their basal end upright or were placed horizontally. The optimal rooting medium for regenerating shoots was MT basal medium supplemented with 0.2 to 0.5 mg.L-1 NAA, and a root induction rate over 80.0% was observed. The selection pressure for kanamycin was 50 mg.L-1. Cefotaxime was used as antibiotics, and the concentration was 300 mg.L-1. After 1.5 months, 14.8% resistant shoots were emerged from the explants. Histochemical GUS assay showed that 22.2% of the resistant plants were GUS-positive. CONCLUSION: Plant regeneration system and Agrobacterium-mediated genetic transformation have been established for M. officinalis in vitro.