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921.
Quorum sensing has attracted much attention due to its involvement in pathologically relevant events such as biofilm formation, virulence factor production, and sporulation. Inhibitors of quorum sensing are important research tools and potential therapeutic agents. In this paper, we describe a phenothiazine structural scaffold as a new type of quorum sensing inhibitors with IC50 values in the single digit micro molar range in Vibrio harveyi. 相似文献
922.
Dongdong Xu Feng You Zhihao Wu Jun Li Jing Ni Zhizhong Xiao Peijun Zhang Yongli Xu 《Genetica》2009,137(2):151-158
Interspecific reciprocal crosses between the two flatfishes Paralichthys olivaceus and P. dentatus yielded hybrids with different viabilities. Specifically, the hybrids of P. olivaceus female and P. dentatus male (HI) were found to be viable, while the reciprocal hybrids from P. dentatus female and P. olivaceus male (HII) were completely inviable. All the HII individuals showed morphological deformities and died before first feeding.
The chromosome analysis showed that HI individuals had the same chromosome number as parents. However, two chromosomes were
missing in HII offspring indicating that the latter were aneuploids. Genomic inheritance from the parents to F1 progeny was also examined by amplified fragment length polymorphism (AFLP) analyses, and the results showed differences between
reciprocal hybrids. Almost all AFLP bands (97.71%) observed in parents were passed on to HI individuals. In contrast, only
86.64% of the AFLP bands from parents were scored in HII individuals. Frequency of lost parental bands was thus significantly
higher in HII than that in HI and intraspecific crosses, which was probably associated with chromosomal elimination. In addition,
higher segregation distortions were found in hybrids than in controls, although these differences were not significant. The
present study indicates that chromosomal elimination and loss of AFLP loci occurred in inviable HII individuals, while such
genomic changes were not found in viable HI individuals. Possible implications of such difference on genomic changes for asymmetric
viability in reciprocal hybrids are discussed. 相似文献
923.
924.
A further phytochemical investigation on the whole plants of Ypsilandra thibetica yielded one sapogenin and 12 spirostanol saponins. Five of these are new compounds, designated as ypsilandrosides C-G (2–6). Their structures were determined by detailed spectroscopic analysis, including extensive 1D and 2D NMR data, and by the result of a hydrolytic reaction. Compounds 2–5 were rare steroidal saponins that an apiofuranosyl unit was directly linked at C-3 of the aglycone. Selected spirostanol saponins (2–6, 9) were tested for their cytotoxic activities against K562, SPC-A-1, BGC-823, Eca-109, and AGS cell lines. Compounds 6 and 9 showed moderate inhibitory activity against all five cell lines. The antifungal properties of the new spirostanol saponins (2–6) against Candida albicans were also determined. 相似文献
925.
Xu Zhang Li Yu Hongtao Bi Xianhua Li Weihua Ni Han Han Nan Li Bingqing Wang Yifa Zhou Guihua Tai 《Carbohydrate polymers》2009,75(3):544-551
Water-soluble polysaccharides isolated from the roots of Panax ginseng C. A. Meyer were completely fractionated into two neutral fractions (WGPN and WGPA-N) and six acidic fractions (WGPA-1-RG, WGPA-2-RG, WGPA-1-HG, WGPA-2-HG, WGPA-3-HG and WGPA-4-HG) by a combination of ethanol precipitation, ion-exchange and gel permeation chromatographies. The analytical results showed that WGPN was a starch-like glucan; WGPA-N was a mixture of starch-like glucan and arabinogalactan; WGPA-1-RG and WGPA-2-RG were composed of major neutral sugars and minor acidic sugars that belong to the type-I rhamnogalacturonan (RG-I)-rich pectins, while fractions WGPA-1-HG to WGPA-4-HG were mainly composed of galacturonic acid (GalA, 62.4–92.1%) and have been identified to be homogalacturonan (HG)-rich pectins with different degrees of methyl-esterification, ranging from 0% to 30%. High performance gel permeation chromatography (HPGPC) showed that the six acidic fractions were homogenous, with molecular weights approximately ranging from 3.5 × 103 to 1.1 × 105. Lymphocyte proliferation assays showed that both the neutral polysaccharides and acidic polysaccharides were potent B and T cell stimulators. 相似文献
926.
X. -Y. Lan Ch. -Y. Pan H. Chen Ch. -Z. Lei F. -Y. Li H. -Y. Zhang Y. -S. Ni 《Journal of applied genetics》2009,50(1):51-54
Concentrations of the single-chain polypeptide hormone prolactin (PRL) are associated with wool or cashmere traits, and its seasonal changes may determine patterns of enzymatic activity and may affect cashmere fibre growth and moult. So, thePRL gene is a potential candidate gene for cashmere traits in marker-assisted selection (MAS). In this paper, we report a novel missense single-nucleotide polymorphism (SNP) within the goatPRL gene in 1367 individuals by PCR-SSCP (polymerase chain reaction with single-strand conformation polymorphism) analysis and DNA sequencing. The novel X76049:g.576C>A mutation is confirmed byEco24I PCR-RFLP (restriction fragment length polymorphism) analysis and causes a missense codon (Pro176Thr). The frequencies of allele C varied from 0.79 to 0.93 in 9 analysed goat populations. C allele was correlated with higher fibre length (P = 0.014). 相似文献
927.
Invertase plays multiple pivotal roles in plant development. Thus, its activity must be tightly regulated in vivo. Emerging evidence suggests that a group of small proteins that inhibit invertase activity in vitro appears to exist in a wide variety of plants. However, little is known regarding their roles in planta. Here, we examined the function of INVINH1, a putative invertase inhibitor, in tomato (Solanum lycopersicum). Expression of a INVINH1:green fluorescent protein fusion revealed its apoplasmic localization. Ectopic overexpression of INVINH1 in Arabidopsis thaliana specifically reduced cell wall invertase activity. By contrast, silencing its expression in tomato significantly increased the activity of cell wall invertase without altering activities of cytoplasmic and vacuolar invertases. Elevation of cell wall invertase activity in RNA interference transgenic tomato led to (1) a prolonged leaf life span involving in a blockage of abscisic acid–induced senescence and (2) an increase in seed weight and fruit hexose level, which is likely achieved through enhanced sucrose hydrolysis in the apoplasm of the fruit vasculature. This assertion is based on (1) coexpression of INVINH1 and a fruit-specific cell wall invertase Lin5 in phloem parenchyma cells of young fruit, including the placenta regions connecting developing seeds; (2) a physical interaction between INVINH1 and Lin5 in vivo; and (3) a symplasmic discontinuity at the interface between placenta and seeds. Together, the results demonstrate that INVINH1 encodes a protein that specifically inhibits the activity of cell wall invertase and regulates leaf senescence and seed and fruit development in tomato by limiting the invertase activity in planta. 相似文献
928.
Effects of the invasive plant Mikania micrantha H.B.K. on soil nitrogen availability through allelopathy in South China 总被引:1,自引:0,他引:1
Allelopathy has been regarded as a mechanism for successful exotic plant invasion. However, it is not clear if and what effects
of allelopathic substances may exert on soil nutrient. The exotic plant Mikania micrantha H.B.K. (M. micrantha) has invaded many forests in south China, and recent studies have suggested it has allelopathic potential for other plants
and soil microbial community. Thus, we hypothesized that M. micrantha could influence soil nutrients and N transformation through allelopathy. We measured total C and N, NO3
−, NH4
+ and pH of the soil beneath M. micrantha and the adjacent open soil, and then measured the above soil properties after treating soil with 3 concentrations of aqueous
extracts of M. micrantha (T1: 0.005 g ml−1; T2: 0.025 g ml−1; T3: 0.100 g ml−1). In addition, a bioassay was conducted to determine the allelopathic potential of the soil beneath M. micrantha. The results showed that M. micrantha significantly affected soil nutrients and N transformation. Soil beneath M. micrantha had inhibitory effects on seed germination and seedling growth of test plant, and had significantly higher C, N, ammonia,
net nitrification rate than those of open soil. The plant extracts decreased soil pH, and T1 decreased it the most, and it increased soil C and N, and T1 represented the greatest increase in both C and N. The extracts also increased both NO3
− and NH4
+ in soil, whereas no significant difference existed among the 3 extract treatments. Compared to the water control, the soil
net mineralization rate was higher under T1, while lower under T2 and T3. However, the extracts increased the soil nitrification rates under all the treatments (T1, T2 and T3). Our results suggest that the water soluble allelochemicals of M. micrantha improve soil nutrient availability, through which the invasive plant M. micrantha may successfully invade and establish in new habitats. 相似文献
929.
930.