肾缺血增强大鼠延髓腹外侧头端区神经元电话动和Fos蛋白表达

在67只切断两侧缓冲神经的麻醉Sprague-Dawley大鼠,应用细胞外记录的电生理方法和免疫组织化学技术,分别观察肾缺血对延髓腹外侧头端区巨细胞旁外侧核神经元自发放电活动和Fos蛋白表达的影响.所得结果如下(1)左肾动脉阻断后,28个单位的放电频率由11.40±1.08增至21.1±1.74spikes/s(P<0.001),血压和心率无明显变化(P>0.05);(2)在17个放电单位中,应用腺苷受体拮抗剂8-苯茶碱(8-phenyltheophylline,10mg/kg)可明显抑制肾缺血的兴奋效应(P<0.05);(3)肾缺血后,延髓腹外侧头端区的Fos蛋白样免疫反应神经元显著增加(P<0.01);(4)预先应用8-苯茶碱可明显减弱肾缺血所激活的Fos蛋白表达反应(P<0.05).以上结果提示肾缺血增强延髓腹外侧头端区神经元的放电活动和Fos蛋白表达,而此作用可能与肾脏缺血所产生的腺苷激活肾内感受器有关.     

Characterization of Tiki,a New Family of Wnt-specific Metalloproteases

The Wnt family of secreted glycolipoproteins plays pivotal roles in development and human diseases. Tiki family proteins were identified as novel Wnt inhibitors that act by cleaving the Wnt amino-terminal region to inactivate specific Wnt ligands. Tiki represents a new metalloprotease family that is dependent on Mn²⁺/Co²⁺ but lacks known metalloprotease motifs. The Tiki extracellular domain shares homology with bacterial TraB/PrgY proteins, known for their roles in the inhibition of mating pheromones. The TIKI/TraB fold is predicted to be distantly related to structures of additional bacterial proteins and may use a core β-sheet within an α+β-fold to coordinate conserved residues for catalysis. In this study, using assays for Wnt3a cleavage and signaling inhibition, we performed mutagenesis analyses of human TIKI2 to examine the structural prediction and identify the active site residues. We also established an in vitro assay for TIKI2 protease activity using FRET peptide substrates derived from the cleavage motifs of Wnt3a and Xenopus wnt8 (Xwnt8). We further identified two pairs of potential disulfide bonds that reside outside the β-sheet catalytic core but likely assist the folding of the TIKI domain. Finally, we systematically analyzed TIKI2 cleavage of the 19 human WNT proteins, of which we identified 10 as potential TIKI2 substrates, revealing the hydrophobic nature of Tiki cleavage sites. Our study provides insights into the Tiki family of proteases and its Wnt substrates.     

Human serum and glucocorticoid-inducible kinase-like kinase (SGKL) phosphorylates glycogen syntheses kinase 3 beta (GSK-3beta) at serine-9 through direct interaction

Serum and glucocorticoid-inducible kinase-like kinase (SGKL) has been identified as a new integrator that decodes lipid signals produced by the activation of phosphoinositide 3-kinase (PI3K). SGKL is activated via its lipid-binding domain (phox homology domain) in response to PI3K signaling. However, downstream targets of SGKL as well as the role of SGKL as a mediator in PI3K signaling in human tissues remain to be established. In this study, we identified human glycogen synthase kinase 3 beta (GSK-3beta) as a specific interacting partner with SGKL in a yeast two-hybrid screening of human brain cDNA library. The association between these two proteins is confirmed independently in human embryonic kidney (HEK293) cells by co-immunoprecipitation. Furthermore, the kinase activity of wild-type SGKL was required for the in vitro phosphorylation of a GSK-3 crosstide fusion protein at serine-21/9 as demonstrated with a Phospho-GSK-3alpha/beta (Ser21/9) specific antibody. The present results provide strong evidences that SGKL could utilize GSK-3beta as a direct downstream target by phosphorylating GSK-3beta at serine-9.     

Aureonitols A and B,Two New C13‐Polyketides from Chaetomium globosum,an Endophytic Fungus in Salvia miltiorrhiza

Two new C₁₃‐polyketides, aureonitols A and B ( 1 and 2 ), along with five known compounds ( 3 – 7 ), were isolated from the solid fermentation culture of the plant endophytic fungus Chaetomium globosum from the aerial parts of Salvia miltiorrhiza. The structures and absolute configurations of 1 and 2 were determined by comprehensive spectroscopic data analysis and computed methods. Compound 5 was found to display the remarkable antimicrobial activities against four multidrug‐resistant bacteria (Enterococcus faecalis, Enterococcus faecium, Staphylococcus aureus, and Staphylococcus epidermidis) with MIC values of 3.13–6.25 μg/mL (ciprofloxacin: 0.78–1.56 μg/mL), and also against all tested fungal strains with MIC values of 3.13–25 μg/mL (ketoconazole: 0.78–12.50 μg/mL).     

Enhanced chemiluminescence enzyme‐linked immunoassay for the determination of DNA methyltransferase 1 in human serum

The occurrence of many diseases is closely related to the high expression of DNA methyltransferase 1 (DNMT1). However, most studies are focused on the detection of DNMT1 activity, a few are concerned with the detection of DNMT1 content. In this study, we developed a simple and highly sensitive chemiluminescence (CL) assay for the detection of DNMT1 content. In this method, anti‐DNMT1 monoclonal antibody was coated on a polystyrene microplate to capture DNMT1. Then anti‐DNMT1 polyclonal antibody and goat anti‐rabbit immunoglobulin G with horseradish peroxidase (IgG‐HRP) were respectively added to combine with captured DNMT1 to form a sandwich structure. Finally, the HRP could catalyze CL substrate and achieve CL signal response. Based on this novel sensitive strategy, the recovery percents were in the ranges from 71.5% to 91.0%. The precision of intra‐assays and inter‐assays were 5.45%–11.29% and 7.03%–11.25%, respectively. The method was successfully applied for the determination of DNMT1 in human serum. The detection results of serum samples showed that the proposed assay had a high correlation with enzyme‐linked immunosorbent assay (ELISA) kit. Compared with the ELISA kit (limit of detection = 0.1 ng/mL), the method has a lower limit of detection of 0.042 ng/mL. Therefore, our method has the potential for the detection of DNMT1 content in clinical diagnosis.     

Comprehensive metabolomic,proteomic and physiological analyses of grain yield reduction in rice under abrupt drought–flood alternation stress

Abrupt drought–flood alternation (T1) is a meteorological disaster that frequently occurs during summer in southern China and the Yangtze river basin, often causing a significant loss of rice production. In this study, the response mechanism of yield decline under abrupt drought–flood alternation stress at the panicle differentiation stage was analyzed by looking at the metabolome, proteome as well as yield and physiological and biochemical indexes. The results showed that drought and flood stress caused a decrease in the yield of rice at the panicle differentiation stage, and abrupt drought–flood alternation stress created a synergistic effect for the reduction of yield. The main reason for the decrease of yield per plant under abrupt drought–flood alternation was the decrease of seed setting rate. Compared with CK0 (no drought and no flood), the net photosynthetic rate and soluble sugar content of T1 decreased significantly and its hydrogen peroxidase, superoxide dismutase, peroxidase activity increased significantly. The identified differential metabolites and differentially expressed proteins indicated that photosynthesis metabolism, energy metabolism pathway and reactive oxygen species response have changed strongly under abrupt drought–flood alteration stress, which are factors that leads to the rice grain yield reduction.     

Absence of estrogen receptor beta leads to abnormal adipogenesis during early tendon healing by an up‐regulation of PPARγ signalling

Achilles tendon injury is one of the challenges of sports medicine, the aetiology of which remains unknown. For a long time, estrogen receptor β (ERβ) has been known as a regulating factor of the metabolism in many connective tissues, such as bone, muscle and cartilage, but little is known about its role in tendon. Recent studies have implicated ERβ as involved in the process of tendon healing. Tendon‐derived stem cells (TDSCs) are getting more and more attention in tendon physiological and pathological process. In this study, we investigated how ERβ played a role in Achilles tendon healing. Achilles tendon injury model was established to analyse how ERβ affected on healing process in vivo. Cell proliferation assay, Western blots, qRT‐PCR and immunocytochemistry were performed to investigate the effect of ERβ on TDSCs. Here, we showed that ERβ deletion in mice resulted in inferior gross appearance, histological scores and, most importantly, increased accumulation of adipocytes during the early tendon healing which involved activation of peroxisome proliferator‐activated receptor γ (PPARγ) signalling. Furthermore, in vitro results of ours confirmed that the abnormity might be the result of abnormal TDSC adipogenic differentiation which could be partially reversed by the treatment of ERβ agonist LY3201. These data revealed a role of ERβ in Achilles tendon healing for the first time, thereby providing a new target for clinical treatment of Achilles tendon injury.     

Access to Bacteriologic-Based Diagnosis in Smear Positive Retreatment Tuberculosis Patients in Rural China: A Cross-Sectional Study in Three Geographic Varied Provinces

Objective

To determine factors influencing the utilization and accessibility to bacteriologic-based tuberculosis (TB) diagnosis among sputum smear positive (SS+) retreatment TB patients, and to develop strategies for improving the case detection rate of MDR-TB in rural China.

Study Design and Setting

A cross-sectional study of SS+ TB retreatment patients was conducted in eight counties from three provinces with different implementation period and strategy of MDR-TB program in China. Demographic and socioeconomic parameters were collected by self-reporting questionnaires. Sputum samples were collected and cultured by the laboratory of county-designated TB clinics and delivered to prefectural Centers for Disease Prevention and Control (CDC) labs for DST with 4 first-line anti-TB drugs.

Results

Among the 196 SS+ retreatment patients, 61.22% received culture tests during current treatment. Patients from more developed regions (OR = 24.0 and 3.6, 95% CI: 8.6–67.3 and 1.1–11.6), with better socio-economic status (OR = 3. 8, 95% CI: 1.3–10.7), who had multiple previous anti-TB treatments (OR = 5.0, 95% CI: 1.6–15.9), and who failed in the most recent anti-TB treatment (OR = 2.6, 95% CI: 1.0–6.4) were more likely to receive culture tests. The percentage of isolates resistant to any of first-line anti-TB drugs and MDR-TB were 50.0% (95% CI: 39.8%-60.2%) and 30.4% (95% CI: 21.0%-39.8%) respectively.

Conclusions

Retreatment SS+ TB patients, high risk MDR-TB population, had poor utilization of access to bacteriologic-based TB diagnosis, which is far from optimal. The next step of anti-TB strategy should be focused on how to make bacteriological-based diagnosis cheaper, safer and more maneuverable, and how to assure the DST-guided treatment for these high-risk TB patients.     

Overexpression of the mango MiCO gene delayed flowering time in transgenic Arabidopsis

Plant Cell, Tissue and Organ Culture (PCTOC) - CONSTANS (CO)/CONSTANS-like (COL) genes play an important role in the photoperiodic flowering pathway. However, the functional roles of the CO/COL...     

Alterations in mitochondrial dynamics with age‐related Sirtuin1/Sirtuin3 deficiency impair cardiomyocyte contractility

Sirtuin1 (SIRT1) and Sirtuin3 (SIRT3) protects cardiac function against ischemia/reperfusion (I/R) injury. Mitochondria are critical in response to myocardial I/R injury as disturbance of mitochondrial dynamics contributes to cardiac dysfunction. It is hypothesized that SIRT1 and SIRT3 are critical components to maintaining mitochondria homeostasis especially mitochondrial dynamics to exert cardioprotective actions under I/R stress. The results demonstrated that deficiency of SIRT1 and SIRT3 in aged (24–26 months) mice hearts led to the exacerbated cardiac dysfunction in terms of cardiac systolic dysfunction, cardiomyocytes contractile defection, and abnormal cardiomyocyte calcium flux during I/R stress. Moreover, the deletion of SIRT1 or SIRT3 in young (4–6 months) mice hearts impair cardiomyocyte contractility and shows aging‐like cardiac dysfunction upon I/R stress, indicating the crucial role of SIRT1 and SIRT3 in protecting myocardial contractility from I/R injury. The biochemical and seahorse analysis showed that the deficiency of SIRT1/SIRT3 leads to the inactivation of AMPK and alterations in mitochondrial oxidative phosphorylation (OXPHOS) that causes impaired mitochondrial respiration in response to I/R stress. Furthermore, the remodeling of the mitochondria network goes together with hypoxic stress, and mitochondria undergo the processes of fusion with the increasing elongated branches during hypoxia. The transmission electron microscope data showed that cardiac SIRT1/SIRT3 deficiency in aging alters mitochondrial morphology characterized by the impairment of mitochondria fusion under I/R stress. Thus, the age‐related deficiency of SIRT1/SIRT3 in the heart affects mitochondrial dynamics and respiration function that resulting in the impaired contractile function of cardiomyocytes in response to I/R.