The essential oil of Sagittaria trifolia, a well-known famous medicinal foodstuff in China, was analyzed for the first time using GC-MS. Twenty-eight constituents were identified. The major ...components of the oil were hexahydrofarnesyl acetone (62.3%), tetramethylhexadecenone (5.8%), myristaldehyde (4.7%), n-pentadecane (2.9%), and 2-hexyldecanol (2.9%).The antimicrobial activity of the essential oil was evaluated against seven microorganisms, including two clinically isolated strains and five reference strains, using microbiological cylinder plate assay and broth microdilution methods. The results showed that the oil had a significant antimicrobial effect on four of them. This antimicrobial activity can partly explain why the oil is used medicinally during childbirth and for skin diseases in Chinese traditional medicine.
1 College of Life and Environment Sciences, Biology Department, Shanghai Normal University, Shanghai 200234, China
2 Ministry of Education Key Laboratory for Biodiversity Science and Ecological ...Engineering, The Institute of Biodiversity Science, Fudan University, Shanghai 200433, China
Correspondence Bo Li bool{at}fudan.edu.cn
To investigate RNA-dependent RNA polymerase (RdRp) further, mutational analysis of the N-terminal domain of the NS5B protein of Classical swine fever virus was performed. Results show that the N-terminal domain (positions 1300) of the protein might be divided artificially into four different regions, N1N4. The N1 region (positions 161) contained neither conserved lysine nor conserved arginine residues. NS5B protein with deletion of the N1 region has the capacity for elongative RNA synthesis, but not for de novo RNA synthesis on natural templates. All substitutions of the conserved lysines and arginines in the N2 region (positions 63216) destroyed RdRp activity completely. Substitutions of the conserved arginines in the N3 region (positions 217280) seriously reduced RdRp activity. However, all substitutions of the conserved lysines in this region enhanced RNA synthesis and made the mutants synthesize RNA on any template. Substitutions of the conserved arginines in the N4 region (positions 281300) reduced elongative synthesis and destroyed de novo RNA synthesis. In contrast, substitutions of lysines in this region did not affect RdRp activity significantly. These data indicate that the N3 region might be related to the enzymic specificity for templates, and the conserved lysines and arginines in different regions have different effects on RdRp activity. In combination with the published crystal structure of bovine viral diarrhea virus NS5B, these results define the important role of the N-terminal domain of NS5B for template recognition and de novo RNA synthesis.
Spartina alterniflora, a perennial grass with C
4-photosynthesis, shows great invading potential in the coastal ecosystems in the east of China. We compared trace gas emissions from
S. alterniflora ...with those from a native C
3 plant,
Phragmites australis, by establishing brackish marsh mesocosms to experimentally assess the effects of plant species (
S. alterniflora vs.
P. australis), flooding status (submerged vs. non-submerged), and clipping (plants clipped or not) on trace gas emissions. The results show that trace gas emission rates were higher in
S. alterniflora than
P. australis mesocosms due to the higher biomass and density of the former, which could fix more available substrates to the soil and potentially emit more trace gases. Meanwhile, trace gas emission rates were higher in non-submerged than submerged soils, suggesting that water might act as a diffusion barrier in the brackish marsh mesocosms. Interestingly, methane (CH
4) emission rates were lower in clipped non-submerged mesocosms than in non-clipped submerged mesocosms, but nitrous oxide (N
2O) emissions were enhanced. CH
4 emissions were significantly correlated with the plant biomass and stem density (
R
2
>
0.48,
P
<
0.05) for both species, suggesting that both the two species might play important roles in CH
4 production and transport and also act as suppliers of easily available substrates for the methanogenic bacteria in wetland ecosystems. N
2O emissions, however, were not significantly correlated with plant biomass and density (
P
>
0.05).
CH sub(4) and N sub(2)O emissions from Spartina alterniflora and Phragmites australis in experimental mesocosms were discussed. It was observed that trace gas emission rates were higher in S. ...alterniflora than P. australis mesocosms due to the higher biomass and density of the former, which could fix more available substrates to the soil and potentially emit more trace gases. Trace gas emission rates were higher in non-submerged than sub-merged soils, suggesting that water might act as a diffusion barrier in the brackish marsh mesocosms. Methane (CH sub(4)) emission rates were loser in clipped non-submerged mesocosms than in non-clipped submerged mesocosms but nitrous oxide emissions were enhanced.
Previously it had been shown that calycosin and calycosin-7-O-β-D-glucoside (CGs) accumulate in whole plants, mainly in leaves, of Astragalus membranaceus Bge. var. mongholicus (Bge.) Hsiao (A. ...mongholicus) plants in response to low temperature. In this work, it was demonstrated that the influences of different conditions on CGs biosynthesis, by examining the changes in CGs content, as well as the expression of related genes, including phenylalanine ammonia lyase (PAL1), cinnamic acid 4-hydroxylase (C4H), chalcone synthase (CHS), chalcone reductase (CHR), chalcone isomerase (CHI), isoflavone synthase (IFS), and isoflavone 3'-hydroxylase (I3'H). The seven gene mRNAs accumulated in leaves of A. mongholicus upon exposure to low temperature in a light-dependent manner, though they exhibited different expression patterns. Transcriptions of CHS, CHR, CHI, IFS, and I3'H of the calycosin-7-O-β-D-glucoside pathway were all up-regulated when plants were transferred from 16 °C to 2 °C or 25 °C or from 2 °C (kept for 24 h) to 25 °C. However, fluctuations in temperature influenced differently the transcriptions of PAL1 and C4H of the general phenylpropanoid pathway in leaves. Moreover, the amount of PAL1 expression changed sharply up and down, consistent with the variation of the content of CGs. PAL enzyme activity appears to be the limiting factor in determining the CGs levels. The inhibitor of PAL enzyme, L-α-aminooxy-β-phenylpropionic acid, almost entirely shut down CGs accumulation at low temperature. All these results confirmed that PAL1, as a smart gene switch, directly controls the accumulation of CGs in A. mongholicus plants, in a light-dependent manner, during low temperature treatment.
The volatile composition of leaves from 14 populations of
Hippophae rhamnoides ssp.
yunnanensis and
H. rhamnoides ssp.
sinensis growing in China was analyzed by gas chromatograph–mass spectrometer ...(GC–MS). Of the 44 compounds represented, 40 were identified. Principal component analysis and cluster analysis were used to investigate the inter-population variability in the composition of volatile compounds. Two main chemotypes were identified, one rich in hexadecanoic acid and eicosanol and the other rich in tetracosane. The hexadecanoic acid and eicosanol-rich chemotype characterizes all seven populations of
H. rhamnoides ssp.
yunnanensis sampled and the tetracosane-rich chemotype all seven populations of
H. rhamnoides ssp.
sinensis.
As a N2-fixing tree species, sea buckthorn (Hippophae rhamnoides) is well adapted to arid regions and is utilized for multiple purposes in China. Current knowledge of genetic variability of H. ...rhamnoides is limited in terms of rangewide distributions. Eleven natural populations of sea buckthorn in northeastern and northwestern China were analyzed to detect genetic variation among and within populations, by use of ISSR (inter-simple sequence repeats) markers. Using eight primers, 207 polymorphic loci were observed, ranging in size from 250 to 2500 bp. The coefficient of gene differentiation (Gst = 0.0679) showed that the total molecular variance of 11 populations was mainly existed within populations. The genetic variation within and among the 11 populations was 93.21 and 6.79%, respectively. No significant correlation between genetic and geographic distances of the populations was found using ISSR markers. Our study provides a population-level genetic profile for further investigation and conservation of genetic diversity of sea buckthorn.
To provide a population-level genetic profile for investigation and conservation of genetic diversity of the sea buckthorn (Hippophae rhamnoides L.), 300 individuals of fifteen natural populations of ...sea buckthorn in China were analyzed by using ISSR (inter-simple sequence repeats) markers. On the basis of Shannon's index and Nei's genetic diversity, the mean genetic diversity detected in the natural populations of Hippophae rhamnoides ssp. yunnanensis, ssp. sinensis, and ssp. gyantsensis was 0.1944, 0.2169, and 0.1372, respectively. The coefficient of gene differentiation (Gst) of seven ssp. yunnanensis populations is 0.2790, and that of seven ssp. sinensis populations is 0.4184. This means that 28% of the total molecular variance of seven ssp. yunnanensis populations existed among populations, and 42% for seven ssp. sinensis populations, suggesting that the subspecies have different genetic structures. No significant correlation between genetic and geographic distances of the populations was found using ISSR markers.
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