CK2 promotes jasmonic acid signaling response by phosphorylating MYC2 in Arabidopsis.

Jasmonic acid (JA) signaling plays a pivotal role in plant development and defense. MYC2 is a master transcription factor in JA signaling, and was found to be phosphorylated and negatively regulated by MAP kinase and receptor-like kinase. However, the kinases that positively regulate MYC2 through phosphorylation and promote MYC2-mediated activation of JA response have not been identified. Here, we identified CK2 as a kinase that phosphorylates MYC2 and thus regulates the JA signaling. CK2 holoenzyme can interact with MYC2 using its regulatory subunits and phosphorylate MYC2 at multiple sites with its catalytic subunits. Inhibition of CK2 activity in a dominant-negative plant line, CK2mut, repressed JA response. On the other hand, increasing CK2 activity by overexpression of CKB4, a regulatory subunit gene of CK2, enhanced JA response in a MYC2-dependent manner. Substitution of the Ser and Thr residues at phosphorylation sites of MYC2 by CK2 with Ala impaired MYC2 function in activating JA response. Further investigations evidenced that CK2 facilitated the JA-induced increase of MYC2 binding to the promoters of JA-responsive genes in vivo. Our study demonstrated that CK2 plays a positive role in JA signaling, and reveals a previously undiscovered mechanism that regulates MYC2 function.

An integrated microfluidics platform with high-throughput single-cell cloning array and concentration gradient generator for efficient cancer drug effect screening.

BACKGROUND: Tumor cell heterogeneity mediated drug resistance has been recognized as the stumbling block of cancer treatment. Elucidating the cytotoxicity of anticancer drugs at single-cell level in a high-throughput way is thus of great value for developing precision therapy. However, current techniques suffer from limitations in dynamically characterizing the responses of thousands of single cells or cell clones presented to multiple drug conditions. METHODS: We developed a new microfluidics-based "SMART" platform that is Simple to operate, able to generate a Massive single-cell array and Multiplex drug concentrations, capable of keeping cells Alive, Retainable and Trackable in the microchambers. These features are achieved by integrating a Microfluidic chamber Array (4320 units) and a six-Concentration gradient generator (MAC), which enables highly efficient analysis of leukemia drug effects on single cells and cell clones in a high-throughput way. RESULTS: A simple procedure produces 6 on-chip drug gradients to treat more than 3000 single cells or single-cell derived clones and thus allows an efficient and precise analysis of cell heterogeneity. The statistic results reveal that Imatinib (Ima) and Resveratrol (Res) combination treatment on single cells or clones is much more efficient than Ima or Res single drug treatment, indicated by the markedly reduced half maximal inhibitory concentration (IC50). Additionally, single-cell derived clones demonstrate a higher IC50 in each drug treatment compared to single cells. Moreover, primary cells isolated from two leukemia patients are also found with apparent heterogeneity upon drug treatment on MAC. CONCLUSION: This microfluidics-based "SMART" platform allows high-throughput single-cell capture and culture, dynamic drug-gradient treatment and cell response monitoring, which represents a new approach to efficiently investigate anticancer drug effects and should benefit drug discovery for leukemia and other cancers.

Crystal structure and ligand identification of odorant binding protein 4 in the natural predator Chrysopa pallens.

Green lacewing Chrysopa pallens (Rambur) is a general predator of many agricultural pests and plays a pivotal role in reducing crop damage by managing insect pest populations. Odorant binding proteins (OBPs) in insects can sense the semiochemicals in the environment and initiate the delivery of signals to their receptors. However, no Chrysopa pallens OBP (CpalOBP) structure has been reported yet, and their corresponding candidate semiochemicals are still largely unknown. Here, we reported the structure of CpalOBP4 solved with X-ray diffraction and showed its potential ligands. Our results showed that CpalOBP4 has a classical OBP structure with six α-helices and three disulfide bridges, and it can bind with farnesene, 2-tridecanone, cis-3-hexenyl hexanoate, nerolidol and farnesol through a central hydrophobic cavity. Our molecular docking results showed that Met31, Met78, Leu98, Phe141, Leu142 and Pro143 in the hydrophobic cavity were the key residues mediating the interaction of CpalOBP4 with farnesene, 2-tridecanone and cis-3-hexenyl hexanoate, which was further proven by the results that mutations of these residues led to significantly reduced binding affinities of CpalOBP4 for these ligands. Our study provides useful information for the further investigation of the biological function of CpalOBP4 as well as important cues for improving biological control in agriculture.

[Propagation of brain injuries from artificial focus into the opposite hemisphere at the early stage of rat electrogenic epilepsy identified by histology and magnetic resonance image].

The purpose of this work was to study the characteristics of rat brain abnormalities at two hemispheres at the early stage of electrogenic epilepsy. Experiments were performed on 37 male Sprague-Dawley rats. Chronically repetitive tetanization (60 Hz, 2 s, 0.4 - 0.6 mA) was used to stimulate the right dorsal hippocampus (DHPC) of the rat brain once a day for 2, 4, 6, 8 or 10 d, respectively. The T(2) weighted magnetic resonance image (T(2)-WI) were obtained from each experimental rat at the end of the experiments. Histological sections were obtained after experimentation. The results showed that the main pathologic changes at the early stage of epilepsy included: (1) T(2)-WI hyperintensification, the histological enlargement of lateral ventricle (LV) and pathological hyperplasia of ventricular choroidea plexus occurred. The pathological hyperplasia was symmetric in two hemispheres, but the LV enlargement was not. (2) Histologically enlarged LV area showed a resemblance to T(2)-WI hyperintensive area. Compared with the control rats, large T(2)-WI hyperintensive area (P=0.0259; P=0.0184; P=0.0184; P=0.0404; P=0.0259) and histologically enlarged LV area (P=0.0210; P=0.01; P=0.0100; P=0.0152) were present in chronically tetanized rats. (3) Dynamic characteristics of histologically enlarged LV area resembled to those of T(2)-WI hyperintensity area in chronically tetanized rats at different stimulating day. Lateralization of T(2)-WI hyperintensity was in accordance with that of T(2)-WI abnormal area and of histologically enlarged LV. These abnormalities were severe on the contralateral side on the stimulating day 6, or on the ipsilateral side on the stimulating day 10. These results imply characteristic propagation of brain abnormalities crossing to the opposite hemisphere at the early stage of an electrogenic rat epilepsy.

[Development and progression in rat brain abnormalities related to early stage of epilepsy measured by magnetic resonance image].

The purpose of the present study was to investigate the features of pathophysiological neural networks in rat temporal lobe epileptogenesis. To establish electrogenic epilepsy model, repetitive tetanization (60 Hz, 2 s, 0.4-0.6 mA) was delivered into the right dorsal hippocampus (HPC) of rat brain. Rats were divided into different groups. Experimental animals received tetanic stimulation once a day for 2, 4, 6, 8 or 10 days, respectively. Primary wet dog shakes (WEDS) of the animals were recorded daily during the stimulation to understand the development of behavioral seizures at early stage of epilepsy. The T(2)-weighted (T(2)-WI) spin-echo images were obtained from each experimental rat. The results demonstrated that T(2)-WI hyperintensity of experimental rats was observed in bilateral symmetric dorsal lateral ventricle (LV) areas at stimulating day 2 (n=4), in contralateral medial and ventral LV areas to the side of the electrode at stimulating day 6 (n=5), in contralateral ventral LV areas at stimulating day 8 (n=3), and in ipsilateral ventral LV areas at stimulating day 10 (n=4). Therefore the peak rate of primary WEDS appeared on stimulating day 4 in the experimental rats. Morphological identification demonstrated that the T(2)-WI signal abnormalities were related to the enlarged LV and pathological ventricular choroidea plexus hyperplasia. The results suggest that the development of rat brain abnormalities from dorsal LV to ventral LV at early stage of epilepsy can be measured by magnetic resonance image, which implies reorganization of pathophysiologically functional networks before kindling effect appear.

[The effects of Erigeron breviscapus preparation on the imaging and neuronal metabolites at the early time points after reperfusion following the ischemic cerebral injury in rats].

OBJECTIVE: To investigate the effects of Erigeron breviscapus preparation on the imaging and neuronal metabolites after reperfusion in the ischemic cerebral injury in rats. METHOD: Twenty-three male Sprague Dawley rats with an average body weight of (165 +/- 15) g (mean +/- S) were used, and were randomly divided into two groups: group A rats (n = 11) underwent an operation of ischemic brain injury, group B rats (n = 12) underwent the same operation and received the treatment of Erigeron breviscapus preparation (1.5 mg.kg-1 weight, i.p.). The right middle cerebral artery occlusion (MCAO) of rats in both groups was induced by 5/0 nylon suture for 2 hours. The reperfusion was conducted for four hours and six hours respectively following MCAO. T2 weighted-imaging (T2WI) and 1H-magnetic resonance spectroscopy (1H-MRS) were performed, to study the changes of the imaging and the neuronal metabolites N-acetyl aspartate (NAA), creatine/phosphocreatine (Cr/PCr), choline (Cho) and lactose (Lac) in cerebrum following cerebral ischemia. RESULT: The hyperintense signals in the right cerebrum in group B decreased compared with those in group A, the T2 values decreased, the level of NAA increased, the ratio of Cr/NAA and Cho/NAA decreased, and no lactose was observed. The brain surface vessels of rats in group B were in the state of dilation. CONCLUSION: Erigeron breviscapus preparation is beneficial to the reestablishment of the blood circulation in the ischemic brain, and to the improvement of the neuronal metabolism and survival.

[Effects of Angelica sinensis injection on the neuronal metabolites and blood flow speed within reperfusion following the ischemic cerebral injury in rats].

AIM: To investigate the effects of Angelica sinensis injection on the neuronal metabolites and blood flow speed within reperfusion in the ischemic cerebral injury of rats. METHODS: Sixty-nine male Sprague Dawley rats with an average body weight of 150 to 170 g were used, and were randomly divided into three groups: sham operation group (n = 4), ischemia injury group (n = 30) underwent an operation of ischemic brain injury, Angelica-treated group (n = 35) underwent the same operation and received the treatment of Angelica sinensis injection (5 g/kg bw, i. p). The right middle cerebral artery occlusion (MCAO) of both ischemia injury group and Angelica-treated group rats was induced by 5/0 nylon suture for 2 hours. The reperfusion was conducted for three to four hours and five to six hours respectively following MCAO. T2 weighted-imaging (T2WI) and 1H magnetic resonance spectroscopy (1H MRS) were performed, to study the changes in imaging and neuronal metabolites N-acetyl aspartate (NAA), creatine/phosphocreatine (Cr/ PCr) and choline (Cho) following cerebral ischemia. The changes in blood flow speed were measured by laser Doppler flowmetry. The surface vascular density in right hemisphere were calculated. RESULTS: The hyperintense signals and volume in the right cerebrum in Angelica-treated group decreased compared with those of the ischemia injury group, the T2 values were decreased, and the level of NAA increased, the ratio of Cr/NAA and Cho/NAA decreased. The blood flow speed in Angelica-treated group was improved. The length of brain surface vessels in group C increased. CONCLUSION: The Angelica sinensis injection enhanced the blood circulation in the ischemic brain, improved the neuronal metabolisms.