5,053 research outputs found
Reactive oxygen species promote chloroplast dysfunction and salicylic acid accumulation in fumonisin B1-induced cell death
AbstractWe report a novel regulatory mechanism by which reactive oxygen species (ROS) regulate fumonisin B1 (FB1)-induced cell death. We found that FB1 induction of light-dependent ROS production promoted the degradation of GFP-labeled chloroplast proteins and increased phenylalanine ammonia lyase (PAL) activity, PAL1 gene expression and SA content, while pretreatment with ROS manipulators reversed these trends. Moreover, treatment with H2O2 or 3-amino-1,2,4-triazole increased PAL activity, PAL1 gene expression and SA content. PAL inhibitor significantly blocked FB1-induced lesion formation and SA increase. Our results demonstrate that light-dependent ROS accumulation stimulates the degradation of chloroplastic proteins and up-regulates PAL-mediated SA synthesis, thus promoting FB1-induced light-dependent cell death
Transferrin, a Cell Pilot and Iron Provider Based on its Interaction with the Overexpressed Transferrin Receptors
Transferrin (Tf) is the serum protein responsible for delivering iron to the erythron and peripheral tissues. Transferrin receptor (TfR), a key receptor in the regulation of iron and is activated by the ferric ion loaded Tf, is overexpressed on the surface of various cancer cells due to their malignant transformation. Based on the Tf-TfR transport mechanism, Tf has been projected to be dually used as a pilot for nanoparticles to target the tumor cells with over expressed TfRs and an intracellular iron provider. Dihydroartemisinin (DHA) is believed a promising tumor therapeutic agent for its unique mechanism of cytotoxicity. When DHA chemically damaging cells, ferrous ions are required to react with the drug. In this research highlight, we discuss our latest published findings which demonstrate the enhanced cytotoxicity of DHA helped with a nanographene oxide carrier and the Tf-TfR transport system, and the potential for its anti-tumor application. This approach gives a further understanding on the role of ligand and receptor in tumor treatments
Molecular mechanisms of cell proliferation induced by low power laser irradiation
Low power laser irradiation (LPLI) promotes proliferation of multiple cells, which (especially red and near infrared light) is mainly through the activation of mitochondrial respiratory chain and the initiation of cellular signaling. Recently, the signaling proteins involved in LPLI-induced proliferation merit special attention, some of which are regulated by mitochondrial signaling. Hepatocyte growth factor receptor (c-Met), a member of tyrosine protein kinase receptors (TPKR), is phosphorylated during LPLI-induced proliferation, but tumor necrosis factor alpha (TNF-alpha) receptor has not been affected. Activated TPKR could activate its downstream signaling elements, like Ras/Raf/MEK/ERK, PI3K/Akt/eIF4E, PI3K/Akt/eNOS and PLC-gamma/PKC pathways. Other two pathways, ΔΨm/ATP/cAMP/JNK/AP-1 and ROS/Src, are also involved in LPLI-induced proliferation. LPLI-induced cell cycle progression can be regulated by the activation or elevated expressions of cell cycle-specific proteins. Furthermore, LPLI induces the synthesis or release of many molecules, like growth factors, interleukins, inflammatory cytokines and others, which are related to promotive effects of LPLI
Elliptic soliton solutions: functions, vertex operators and bilinear identities
We establish a bilinear framework for elliptic soliton solutions which are
composed by the Lam\'e-type plane wave factors. functions in Hirota's
form are derived and vertex operators that generate such functions are
presented. Bilinear identities are constructed and an algorithm to calculate
residues and bilinear equations is formulated. These are investigated in detail
for the KdV equation and sketched for the KP hierarchy. Degenerations by the
periods of elliptic functions are investigated, giving rise to the bilinear
framework associated with trigonometric/hyperbolic and rational functions.
Reductions by dispersion relation are considered by employing the so-called
elliptic -th roots of the unity. functions, vertex operators and
bilinear equations of the KdV hierarchy and Boussinesq equation are obtained
from those of the KP. We also formulate two ways to calculate bilinear
derivatives involved with the Lam\'e-type plane wave factors, which shows that
such type of plane wave factors result in quasi-gauge property of bilinear
equations.Comment: 41 page
The Lam\'e functions and elliptic soliton solutions: Bilinear approach
The Lam\'e function can be used to construct plane wave factors and solutions
to the Korteweg-de Vries (KdV) and Kadomtsev-Petviashvili (KP) hierarchy. The
solutions are usually called elliptic solitons. In this chapter, first, we
review recent development in the Hirota bilinear method on elliptic solitons of
the KdV equation and KP equation, including bilinear calculations involved with
the Lam\'e type plane wave factors, expressions of functions and the
generating vertex operators. Then, for the discrete potential KdV and KP
equations, we give their bilinear forms, derive functions of elliptic
solitons, and show that they share the same vertex operators with the KdV
hierarchy and the KP hierarchy, respectively.Comment: 24 page
Three new synonyms of Pohlia (Bryaceae) from China
Three species of Webera and Pohlia described from China were reduced to new synonyms of other species of Pohlia. Webera ciliifera Broth. is a synonym of Pohlia elongata Hedw., W. pygmaea Broth. is a synonym of P. minor Schleich. ex Schwaegr. and P. subflexuosa Broth. is a synonym of P. flexuosa Hook
Phosphatidylinositol 3-Kinase Plays a Vital Role in Regulation of Rice Seed Vigor via Altering NADPH Oxidase Activity
Phosphatidylinositol 3-kinase (PI3K) has been reported to be important in normal plant growth and stress responses. In this study, it was verified that PI3K played a vital role in rice seed germination through regulating NADPH oxidase activity. Suppression of PI3K activity by inhibitors wortmannin or LY294002 could abate the reactive oxygen species (ROS) formation, which resulted in disturbance to the seed germination. And then, the signal cascades that PI3K promoted the ROS liberation was also evaluated. Diphenylene iodonium (DPI), an NADPH oxidase inhibitor, suppressed most of ROS generation in rice seed germination, which suggested that NADPH oxidase was the main source of ROS in this process. Pharmacological experiment and RT-PCR demonstrated that PI3K promoted the expression of Os rboh9. Moreover, functional analysis by native PAGE and the measurement of the 2, 3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazo-lium-5- carboxanilide (XTT) formazan concentration both showed that PI3K promoted the activity of NADPH oxidase. Furthermore, the western blot analysis of OsRac-1 demonstrated that the translocation of Rac-1 from cytoplasm to plasma membrane, which was known as a key factor in the assembly of NADPH oxidase, was suppressed by treatment with PI3K inhibitors, resulting in the decreased activity of NADPH oxidase. Taken together, these data favored the novel conclusion that PI3K regulated NADPH oxidase activity through modulating the recruitment of Rac-1 to plasma membrane and accelerated the process of rice seed germination
Extrapolative Beliefs in the Cross-Section: What Can We Learn from the Crowds?
Using novel data from a crowdsourcing platform for ranking stocks, we investigate how investors form expectations about stock returns over the next week. We find that investors extrapolate from stocks’ recent past returns, with more weight on more recent returns, especially when recent returns are negative, salient, or from a dispersed cross-section. Such extrapolative beliefs are stronger among nonprofessionals and large stocks. Moreover, consensus rankings negatively predict returns over the next week, more so among stocks with low institutional ownership and a high degree of extrapolation. A trading strategy that sorts stocks on investor beliefs generates an economically significant profit
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