Qingshan Du's scientific contributionswhile working at East China University of Science and Technology (Shanghai, China) and other institutions
- Abstract: Based on the hypoxia prodrug moiety of p-nitrobenzyl, a selective ratiometric fluorescent sensor (RHP) for the detection of microenvironment hypoxia was designed and synthesized. RHP can be selectively activated by bioreductive enzymes (NTR) and results in an evident blue to green fluorescent emission wavelength change in both solution phases and in cell lines, which might be the first fluorescent ratiometric probe for hypoxia in solid tumors.
- Abstract: Plant activators are a novel kind of agrochemicals that could induce resistance in many plants against a broad spectrum of diseases. To date, only few plant activators have been commercialized. In order to develop novel plant activators, a series of benzo-1,2,3-thiadiazole-7-carboxylate derivatives were synthesized, and the structures were characterized by (1)H NMR, IR, elemental analyses, and HRMS or MS. Their potential systemic acquired resistance as plant activators was evaluated as well.... Show More
- Abstract: Background: Plant cell suspension culture of Vitis vinifera is a promising technology for investigating different factors that are able to induce and/or modify stilbenes biosynthesis. Jasmonates have been reported to play an important role in a signal transduction pathway that regulates defence responses as well as the production of secondary metabolites. In this study, 2, 3-dihydroxypropyl jasmonate (DHPJA) was used to investigate its effect on stimulating trans-resveratrol (t-R)... Show More
Publications citing this author (116)
[Show abstract] [Hide abstract] ABSTRACT: An extract from Botrytis cinerea culture filtrate was sprayed on grapevine plants (Vitis vinifera) to investigate its potential to stimulate defense reactions. The extract triggered the induction of genes encoding pathogenesis-related (PR) proteins as chitinases (CHIT), polygalacturonase-inhibiting protein (PGIP), serine proteinase inhibitor (PIN), and enzymes involved in phytoalexin synthesis as phenylalanine ammonia-lyase (PAL) and stilbene synthase (STS). Correlated to the up-regulation of these latter genes, stilbene content increased in treated leaves. Consequently, treatment of grapevine leaves with the fungal extract triggered protection toward Plasmopara viticola and Erysiphe necator, the causal agents of grapevine downy and powdery mildews, respectively. Disease severity was significantly reduced in elicited plants, approximately 61 % for downy mildew and 83 % for powdery mildew. This approach could represent a valuable strategy to protect grapevine from diseases as an alternative or complementary method to the use of pesticides.
- Phenylalanine ammonia-lyase (PAL), the first enzyme of the phenylpropanoid pathway, is involved in the biosynthesis of various defense-related compounds (phenolics, lignin, salicylic acid). In this pathway, downstream of PAL, stilbene synthase (STS) catalyzes the synthesis of resveratrol, the main phytoalexin produced by grapevine in response to biotic or abiotic stresses (Adrian et al. 1997;Coutos-Thévenot et al. 2001; Langcake and Pryce 1977a; Langcake and Pryce 1977b;Shen et al. 2012). Expression of PAL and STS was highly induced in response to Bc extract treatment.
[Show abstract] [Hide abstract] ABSTRACT: Centella asiatica is a perrenial herb that grows in tropical regions with numerous medicinal properties mostly attributed to the presence of pentacyclic triterpenoids. Interestingly, this plant also possess a significant amount of phenylpropanoid-derived chlorogenic acids (CGAs) that have recently been reported to confer neuroprotective properties. In a biotechnological attempt to increase the biosynthesis of CGA-derivatives in cultured Centella cells, acibenzolar-S-methyl was applied as a xenobiotic inducer in combination with quinic acid and shikimic acid as precursor molecules. Applying a semi-targeted metabolomics-based approach, time and concentration studies were undertaken to evaluate the effect of the manipulation on cellular metabolism leading to CGA production. Phytochemical extracts were prepared using methanol and analyzed using a UHPLC-qTOF-MS platform. Data was processed and analyzed using multivariate data models. A total of four CGA-derivatives, annotated as trans-5-feruloylquinic acid, 3,5 di-caffeoylquinic acid, 3,5-O-dicaffeoyl-4-O-malonylquinic acid (irbic acid) and 3-caffeoyl, 5-feruloylquinic acid, were found to be upregulated by the acibenzolar-S-methyl treatment. To the best of our knowledge, this is the first report on the induction of CGA derivatives in this species. Contrary to expectations, the effects of precursor molecules on the levels of the CGAs were insignificant. However, a total of 16 metabolites, including CGA derivatives, were up-regulated by precursor treatment. Therefore, this study shows potential to biotechnologically manipulate C. asiatica cells to increase the production of these health beneficial CGAs.
- However, these inducers seemingly have different effects on the concentration of CGAderivatives in C. asiatica cells. Therefore, the enhancement of the already existing phenylpropanoid pathway (where SA failed) is in agreement with the notion that ASM is a more effective inducer of the pathway compared to SA (Du et al., 2012; Sillero et al., 2012). In addition, the presence of only these biomarkers in SA-and ASM-treated C. asiatica cells could be an indication that the enzymatic machinery of this plant predominately catalyze the biosynthesis of only these CGA-derivatives.
[Show abstract] [Hide abstract] ABSTRACT: Hypoxia is an intensively investigated condition with profound effects on cell metabolism, migration, and angiogenesis during development and disease. Physiologically, hypoxia is linked to tissue homeostasis and maintenance of pluripotency. Hypoxia also contributes to pathologies including cardiovascular diseases and cancer. Despite its importance, microscopic visualization of hypoxia is largely restricted to the detection of reductively activated probes by immunostaining. Here, we describe a novel family of genetically encoded fluorescent sensors that detect the activation of HIF transcription factors reported by the oxygen-independent fluorescent protein UnaG. It comprises sensors with different switching and memory behavior and combination sensors that allow the distinction of hypoxic and reoxygenated cells. We tested these sensors on orthotopically transplanted glioma cell lines. Using a cranial window, we could visualize hypoxia intravitally at cellular resolution. In tissue samples, sensor activity was detected in regions, which were largely devoid of blood vessels, correlated with HIF-1α stabilization, and were highly heterogeneous at a cellular level. Frequently, we detected recently reoxygenated cells outside hypoxic areas in the proximity of blood vessels, suggestive of hypoxia-promoted cell migration.
- Therefore, precise knowledge of the hypoxic state of a tumor not only provides a valuable entry point to understanding tumor progression, but also holds considerable prognostic value (Bussink et al, 2003). A collection of techniques are available to assess hypoxia in living tissues or tissue preparations (Kiyose et al, 2010; Cui et al, 2011 ). Assays that rely on tissue disaggregation or invasive polarographic needle and fluorescence-based fiber-optic probe measurements suffer from their inability to provide information on hypoxia and tissue architecture (Raleigh et al, 1996).