No abstract

Eucommia ulmoides Oliver is a traditional medicinal plant of China, and it is one of the main sources of chlorogenic acid. Chlorogenic acid is an ester of caffeic acid, quinic acid, and a phenolic compound that has antibacterial, antifungal, antioxidant, and antitumor activities. The purpose of this study was to determine whether endophytic fungi isolated from Eucommia ulmoides Oliver had the same ability to produce chlorogenic acid. Primary screening was done by antibacterial and antifungal reactions, and the strain reselection was done with high-performance liquid chromatography (HPLC) to identify the fermentation products of the selected strains. Extracts of the leaf and cortex of Eucommia ulmoides Oliver were also deteted by HPLC, then positive results of HPLC were analyzed by GC-MS and LC-MS. In this study, 29 strains were isolated from Eucommia ulmoides Oliver. Most of them had antibacterial activity, and a few of them had antifungal activity. One ingredient of the B5 extract had a retention time identical to that of authentic chlorogenic acid. With GC-MS, other ingredients, isocoumarin and p-chlorocinnamide, were found. With LC-MS, chlorogenic acid and geniposide related to Eucommia ulmoides Oliver were found. The strain B5 was identified as Sordariomycete sp. Thus, endophytic fungi may produce the bioactive compound chlorogenic acid, as their host plant does, and could be used for the production of chlorogenic acid by fermentation in the future.

Abstract:Eucalyptus oil possesses a wide spectrum of biological activity, including anti-microbial, fungicidal, herbicidal, acaricidal and nematicidal properties. We studied anti-fungal activities of the leaf oil extracted from Eucalyptus. grandisˆE. urophylla. Eleven plant pathogenic fungi were tested based on the mycelium growth rates with negative control. The results showed that Eucalyptus oil has broad-spectrum inhibitory effects toward these fungi. Remarkable morphological and structural alterations of hypha have been observed for Magnaporthe grisea after the treatment. The mRNA genome array of M. grisea was used to detect genes that were differentially expressed in the test strains treated by the Eucalyptus oil than the normal strains. The results showed 1919 genes were significantly affected, among which 1109 were down-regulated and 810 were up-regulated (p < 0.05, absolute fold change >2). According to gene ontology annotation analysis, these differentially expressed genes may cause abnormal structures and physiological function disorders, which may reduce the fungus growth. These results show the oil has potential for use in the biological control of plant disease as a green biopesticide.

This study detected the upstream and downstream key genes of glycolysis in Dunaliella Salina by using Real-time FluorescenceQuantitative PCR assays and measurement of enzyme activity. The results were as follows: the levels of transcription, enzyme activity, and protein of D. salina PFK were up-regulated under hyperosmotic stress while D. salina ENO were down-regulated. At the same time we monitored the change of intracellular degradation of starch, the synthesis of glycerol and PEP concentration in Dunaliella Salina under hyperosmotic stress. We found that lower expression of DsENO reduced the concentration of intracellular PEP which promoted the degradation of starch, and decreased the flow of carbon into the tricarboxylic acid cycle which would favor the synthesis of glycerol.

The Dunaliella salina enolase gene (DsENO) had been cloned using Rapid Amplification of cDNA Ends methods. Recombinant D. salina enolase was over-expressed in E. coli BL21 and purified. Native polyacrylamide gel electrophoresis of recombinant enolase indicated that it forms a homo-dimer in the native state. Polyclonal antiserum against purified recombinant D. salina enolase was raised in a rabbit. The enolase activity of DsENO was examined in Kluyveromyces lactis enolase null mutant and DsENO partly complemented the enolase null mutant of K. lactis Rag À phenotype. The protein level of D. salina enolase was determined under various conditions. The enolase protein level decreased by more than 50% after between 1.5-and 3-h exposure to hyperosmotic salt stress. This was confirmed by the enolase activity assay. It is suggested that enolase takes part in glycerol synthesis, which can balance the external salt concentration. Under heat-shock treatment, induction of enolase was observed, which suggested that D. salina enolase may contribute to its thermal tolerance.