Verification and tissue-specific expression of nifU-like gene from the amphioxus Branchiostoma belcheri

A nifU-like gene exhibiting similarity to nifU of nitrogen fixation gene cluster was identified for the first time from the gut cDNA library of amphioxus Branchiostoma belcheri. Both RT-PCR and Northern blotting as well as in situ hybridization histochemistry verified that the cDNA represents an amphioxus nifU-like gene rather than a microbial contaminant. The nifU-like gene encodes a protein of 164 amino acid residues including a highly conserved U-type motif (C-X26-C-X43-C), and shares 66-86% identity to NifU-like proteins from a variety of species including vertebrates, invertebrates and microbes. It is expressed in a tissue-specific manner in the digestive system including epipharyngeal groove, endostyle, hepatic caecum and hind-gut and in the gill, ovary and testis. Taken together, it is highly likely that NifU-like protein plays some tissue-dependent and critical role in amphioxus.     

Discovery of benzimidazole derivatives as novel multi-target EGFR, VEGFR-2 and PDGFR kinase inhibitors

Multi-target EGFR, VEGFR-2 and PDGFR inhibitors are highly useful anticancer agents with improved therapeutic efficacies. In this work, we used two virtual screening methods, support vector machines (SVM) and molecular docking, to identify a novel series of benzimidazole derivatives, 2-aryl benzimidazole compounds, as multi-target EGFR, VEGFR-2 and PDGFR inhibitors. 2-Aryl benzimidazole compounds were synthesized and their biological activities against a tumor cell line HepG-2 and specific kinases were evaluated. Among these compounds, compounds 5a and 5e exhibited high cytotoxicity against HepG-2 cells with IC?? values at ～2 μM. Further kinase assay study showed that compound 5a have good EGFR inhibitory activity and moderate VEGFR-2 and PDGFR inhibitory activities, while 5e have moderate EGFR inhibitory activity and slightly weaker VEGFR-2 and PDGFR inhibitory activities. Molecular docking analysis suggested that compound 5a more tightly interacts with EGFR and PDGFR than compound 5e. Our study discovered a novel series of benzimidazole derivatives as multi-target EGFR, VEGFR-2 and PDGFR kinases inhibitors.     

FERONIA is involved in phototropin 1-mediated blue light phototropic growth in Arabidopsis

Plant shoot phototropism is triggered by the formation of a light-driven auxin gradient leading to bending growth. The blue light receptor phototropin 1(phot1) senses light direction, but how this leads to auxin gradient formation and growth regulation remains poorly understood. Previous studies have suggested phot1’s role for regulated apoplastic acidification, but its relation to phototropin and hypocotyl phototropism is unclear. Herein, we show that blue light can cause phot1 to interact with...     

Flavonoids from Potentilla parvifolia Fisch. and Their Neuroprotective Effects in Human Neuroblastoma SH‐SY5Y Cells in vitro

Potentilla parvifolia Fisch . (Rosaceae) is a traditional medicinal plant in P. R. China. In this study, seven flavonoids, ayanin ( 1 ), tricin ( 2 ), quercetin ( 3 ), tiliroside ( 4 ), miquelianin ( 5 ), isoquercitrin ( 6 ), and astragalin ( 7 ), were separated and purified from ethyl acetate extractive fractions from ethanol extracts of P. parvifolia using a combination of sevaral chromatographic methods. The human neuroblastoma SH‐SY5Y cells were differentiated with all trans‐retinoic acid and treated with okadaic acid to induce tau protein phosphorylation and synaptic atrophy, which could establish an Alzheimer's disease cell model. The neuroprotective effects of these flavonoids in cellular were evaluated in vitro by this cell model. Results from the Western blot and morphology analysis suggested that compounds 3 and 4 had the better neuroprotective effects.     

TNFα-initiated oxidative/nitrative stress mediates cardiomyocyte apoptosis in traumatic animals

Whole body non-penetrating trauma causes myocardial infarction in humans and mechanical trauma (MT) results in cardiac dysfunction in animals. Our recent study demonstrated that incubation of cardiomyocytes with plasma isolated from MT animals causes significant cardiomyocyte apoptosis that can be blocked by neutralization of TNFα. The present study attempted to obtain direct in vivo evidence to support that overproduction of TNFα plays a causative role in trauma-induced cardiomyocyte apoptosis. Non-lethal MT caused significant TNFα overproduction (2.4-fold at 1.5 h after MT) and increased cardiomyocyte apoptosis (starting 3 h and peaking 12 h after MT). Pharmacological inhibition of TNFα with etanercept or TNFα gene deletion reduced post-trauma myocyte apoptosis (P < 0.01). Expression of iNOS and NADPH oxidase, overproduction of NO and , and excessive protein nitration in the MT heart were all significantly reduced in etanercept-treated or TNFα^−/− mice, suggesting that oxidative/nitrative stress may contribute to TNFα-initiated myocyte apoptosis in MT hearts. Additional experiments demonstrated that inhibiting iNOS (1400W) or NADPH oxidase (apocynin), or scavenging peroxynitrite (FP15) significantly reduced myocyte apoptosis in MT animals (P < 0.01). Collectively, these data demonstrated that non-lethal mechanical trauma caused significant TNFα production that in turn stimulated myocardial apoptosis via oxidative/nitrative stress.     

Over-expression of OSRIP18 increases drought and salt tolerance in transgenic rice plants

Both drought and high salinity stresses are major abiotic factors that limit the yield of agricultural crops. Transgenic techniques have been regarded as effective ways to improve crops in their tolerance to these abiotic stresses. Functional characterization of genes is the prerequisite to identify candidates for such improvement. Here, we have investigated the biological functions of an Oryza sativa Ribosome-inactivating protein gene 18 (OSRIP18) by ectopically expressing this gene under the control of CaMV 35S promoter in the rice genome. We have generated 11 independent transgenic rice plants and all of them showed significantly increased tolerance to drought and high salinity stresses. Global gene expression changes by Microarray analysis showed that more than 100 probe sets were detected with up-regulated expression abundance while signals from only three probe sets were down-regulated after over-expression of OSRIP18. Most of them were not regulated by drought or high salinity stresses. Our data suggested that the increased tolerance to these abiotic stresses in transgenic plants might be due to up-regulation of some stress-dependent/independent genes and OSRIP18 may be potentially useful in further improving plant tolerance to various abiotic stresses by over-expression.     

Golgi‐localized cation/proton exchangers regulate ionic homeostasis and skotomorphogenesis in Arabidopsis

Multiple transporters and channels mediate cation transport across the plasma membrane and tonoplast to regulate ionic homeostasis in plant cells. However, much less is known about the molecular function of transporters that facilitate cation transport in other organelles such as Golgi. We report here that Arabidopsis KEA4, KEA5, and KEA6, members of cation/proton antiporters‐2 (CPA2) superfamily were colocalized with the known Golgi marker, SYP32‐mCherry. Although single kea4,5,6 mutants showed similar phenotype as the wild type under various conditions, kea4/5/6 triple mutants showed hypersensitivity to low pH, high K⁺, and high Na⁺ and displayed growth defects in darkness, suggesting that these three KEA‐type transporters function redundantly in controlling etiolated seedling growth and ion homeostasis. Detailed analysis indicated that the kea4/5/6 triple mutant exhibited cell wall biosynthesis defect during the rapid etiolated seedling growth and under high K⁺/Na⁺ condition. The cell wall‐derived pectin homogalacturonan (GalA)₃ partially suppressed the growth defects and ionic toxicity in the kea4/5/6 triple mutants when grown in the dark but not in the light conditions. Together, these data support the hypothesis that the Golgi‐localized KEAs play key roles in the maintenance of ionic and pH homeostasis, thereby facilitating Golgi function in cell wall biosynthesis during rapid etiolated seedling growth and in coping with high K⁺/Na⁺ stress.