Molecular identification and functional analysis of Niemann-Pick type C2 protein in Macrocentrus cingulum Brischke (Hymenoptera: Braconidae)

Niemann-Pick type C2 (NPC2) proteins in arthropods have been extensively differentiated and possibly duplicated according to environmental conditions and are probable to have different functions. The participation of NPC2 proteins in chemical communication in arthropods brings new objectives in environmental-friendly strategies for pest population control. In this study, NPC2 gene in Macrocentrus cingulum (McinNPC2) was newly identified by rapid amplification cDNA ends (RACE) technology. McinNPC2 amino acid sequence alignment with other representative NPC2 annotates to evaluate the highly conserved consensus amino acids, but with odorant binding proteins in M. cingulum show that only one consensus amino acid. Primary six-cysteine structures that are same to odorant binding proteins in M. cingulum were observed in McinNPC2. Phylogenetic analysis of McinNPC2 indicated that the nearest monophyletic group forming one clade with high posterior probability values clusters as Cyphomyrmex costatus (CcosNPC2) whereas the nearest evolutionary relation group as some odorant binding proteins. Moreover, quantitative real-time PCR (qPCR) measurements show that the McinNPC2 gene expression level in various tissues of the female is significantly and ubiquitously higher than in male, whereas the highest expression level in female antennae. We further explore the binding characterization of recombinant McinNPC2 to candidate odor molecules and did the modeling and docking simulations. The results showed ligands binding specificity and docking tests results indicate that β-ionone, an aroma compound commonly found in essential oils, can strongly bind with McinNPC2. In conclusion, we proposed that McinNPC2 may be involved in chemical communication and play roles in perception of plant volatiles.     

禾谷镰刀菌蛋白激酶研究进展

由禾谷镰刀菌引起的小麦赤霉病是小麦生产最重要的真菌病害之一,除了造成严重的产量损失外,其病原菌还会产生多种真菌毒素危害人畜健康。蛋白激酶在禾谷镰刀菌生长发育、植物侵染和胁迫应答等方面具有重要作用。综述了禾谷镰刀菌主要蛋白激酶在生物学功能和分子作用机制等方面的研究进展,并对未来禾谷镰刀菌蛋白激酶的研究趋势进行了展望,以期为今后禾谷镰刀菌蛋白激酶的研究与小麦赤霉病的防治提供理论参考。     

18O-Labeled Adenosine and 9-(β-D-Arabinofuranosyl)Adenine (ARA-A): Synthesis,Mass Spectrometry,and Studies of 18O-Induced 13C NMR Chemical Shifts

Abstract

[2′-¹⁸O]- and [3′-¹⁸O]-Adenosine and [2′-¹⁸O]- and [3′-¹⁸O]-9-(β-D-arabinofuranosyl) adenine were synthesized from^?appropriate nucleoside precursors. The sites of ¹⁸O-incorporation were determined by mass spectrometry. ¹⁸O-Induced ¹³C NMR shifts were measured for 2′-and 3′-labeled adenosines as 1.2 and 1.6 Hz, respectively.     

Construction of ploidy series of Saccharomyces cerevisiae by the plasmid YCplac33-GHK

An effective approach, using the plasmid YCplac33-GHK, is developed to construct a ploidy series of Saccharomyces cerevisiae. YCplac33-GHK harbors the HO gene under the control of galactose-inducible promoter and KanMX4 as the selective marker. The simple method can solve the problem of industrial applications of strains with resistance genes.     

Impairment of TrkB-PSD-95 Signaling in Angelman Syndrome

Angelman syndrome (AS) is a neurodevelopment disorder characterized by severe cognitive impairment and a high rate of autism. AS is caused by disrupted neuronal expression of the maternally inherited Ube3A ubiquitin protein ligase, required for the proteasomal degradation of proteins implicated in synaptic plasticity, such as the activity-regulated cytoskeletal-associated protein (Arc/Arg3.1). Mice deficient in maternal Ube3A express elevated levels of Arc in response to synaptic activity, which coincides with severely impaired long-term potentiation (LTP) in the hippocampus and deficits in learning behaviors. In this study, we sought to test whether elevated levels of Arc interfere with brain-derived neurotrophic factor (BDNF) TrkB receptor signaling, which is known to be essential for both the induction and maintenance of LTP. We report that TrkB signaling in the AS mouse is defective, and show that reduction of Arc expression to control levels rescues the signaling deficits. Moreover, the association of the postsynaptic density protein PSD-95 with TrkB is critical for intact BDNF signaling, and elevated levels of Arc were found to impede PSD-95/TrkB association. In Ube3A deficient mice, the BDNF-induced recruitment of PSD-95, as well as PLCγ and Grb2-associated binder 1 (Gab1) with TrkB receptors was attenuated, resulting in reduced activation of PLCγ-α-calcium/calmodulin-dependent protein kinase II (CaMKII) and PI3K-Akt, but leaving the extracellular signal-regulated kinase (Erk) pathway intact. A bridged cyclic peptide (CN2097), shown by nuclear magnetic resonance (NMR) studies to uniquely bind the PDZ1 domain of PSD-95 with high affinity, decreased the interaction of Arc with PSD-95 to restore BDNF-induced TrkB/PSD-95 complex formation, signaling, and facilitate the induction of LTP in AS mice. We propose that the failure of TrkB receptor signaling at synapses in AS is directly linked to elevated levels of Arc associated with PSD-95 and PSD-95 PDZ-ligands may represent a promising approach to reverse cognitive dysfunction.     

SUMOylation of PPARγ by Rosiglitazone Prevents LPS-Induced NCoR Degradation Mediating Down Regulation of Chemokines Expression in Renal Proximal Tubular Cells

Rosiglitazone (RGL), a synthetic agonist for peroxisome proliferator activated receptor γ (PPARγ), exhibits a potent anti-inflammatory activity by attenuating local infiltration of neutrophils and monocytes in the renal interstitium. To evaluate the mechanisms that account for inhibiting inflammatory cells infiltration, we investigated the effect of RGL on chemokines secretion and nuclear factor-kappa B (NF-κB) activation in human renal proximal tubular cells (PTCs). We demonstrated that RGL significantly inhibited lipopolysaccharide (LPS)-induced interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) production in a dose-dependent manner, without appreciable cytotoxicity. Chromatin immunoprecipitation (ChIP) assays clearly revealed that, RGL inhibited p65 binding to IL-8/MCP-1 gene promoters in LPS-stimulated PTCs. Interestingly, further experiments showed RGL reversed LPS-induced nuclear receptor corepressor (NCoR) degradation. In addition, knockdown of protein inhibitor of activated STAT1 (PIAS1), an indispensable small ubiquitin-like modifier (SUMO) ligase, abrogated the effects of RGL on antagonizing LPS-induced IL-8/MCP-1 overexpression and NCoR degradation. These findings suggest that, RGL activates PPARγ SUMOylation, inhibiting NCoR degradation and NF-κB activation in LPS-stimulated PTCs, which in turn decrease chemokines expression. The results unveil a new mechanism triggered by RGL for prevention of tubular inflammatory injury.     

Longitudinal Variability of Phosphorus Fractions in Sediments of a Canyon Reservoir Due to Cascade Dam Construction: A Case Study in Lancang River,China

Dam construction causes the accumulation of phosphorus in the sediments of reservoirs and increases the release rate of internal phosphorus (P) loading. This study investigated the longitudinal variability of phosphorus fractions in sediments and the relationship between the contents of phosphorus fractions and its influencing factors of the Manwan Reservoir, Lancang River, Yunnan Province, China. Five sedimentary phosphorus fractions were quantified separately: loosely bound P (ex-P); reductant soluble P (BD-P); metal oxide-bound P (NaOH-P); calcium-bound P (HCl-P), and residual-P. The results showed that the total phosphorus contents ranged from 623 to 899 µg/g and were correlated positively with iron content in the sediments of the reservoir. The rank order of P fractions in sediments of the mainstream was HCl-P>NaOH-P>residual-P>BD-P>ex-P, while it was residual-P>HCl-P>NaOH-P>BD-P>ex-P in those of the tributaries. The contents of bio-available phosphorus in the tributaries, including ex-P, BD-P and NaOH-P, were significantly lower than those in the mainstream. The contents of ex-P, BD-P, NaOH-P showed a similar increasing trend from the tail to the head of the Manwan Reservoir, which contributed to the relatively higher content of bio-available phosphorus, and represents a high bio-available phosphorus releasing risk within a distance of 10 km from Manwan Dam. Correlation and redundancy analyses showed that distance to Manwan Dam and the silt/clay fraction of sediments were related closely to the spatial variation of bio-available phosphorus.     

Ginsenoside Rg-1 Protects Retinal Pigment Epithelium (RPE) Cells from Cobalt Chloride (CoCl2) and Hypoxia Assaults

Severe retinal ischemia causes persistent visual impairments in eye diseases. Retinal pigment epithelium (RPE) cells are located near the choroidal capillaries, and are easily affected by ischemic or hypoxia. Ginsenoside Rg-1 has shown significant neuroprotective effects. This study was performed to test the cytoprotective effect of ginsenoside Rg-1 in RPE cells against hypoxia and cobalt chloride (CoCl₂) assaults, and to understand the underlying mechanisms. We found that Rg-1 pre-administration significantly inhibited CoCl₂- and hypoxia-induced RPE cell death and apoptosis. Reactive oxygen specisis (ROS)-dependent p38 and c-Jun NH(2)-terminal kinases (JNK) MAPK activation was required for CoCl₂-induced RPE cell death, and Rg-1 pre-treatment significantly inhibited ROS production and following p38/JNK activation. Further, CoCl₂ suppressed pro-survival mTOR complex 1 (mTORC1) activation in RPE cells through activating of AMP-activated protein kinase (AMPK), while Rg-1 restored mTORC1 activity through inhibiting AMPK activation. CoCl₂-induced AMPK activation was also dependent on ROS production, and anti-oxidant N-acetylcysteine (NAC) prevented AMPK activation and RPE cell death by CoCl₂. Our results indicated that Rg-1 could be further investigated as a novel cell-protective agent for retinal ischemia.