Kp-10 promotes bovine mammary epithelial cell proliferation by activating GPR54 and its downstream signaling pathways

It has been reported that the proliferation and apoptosis of mammary epithelial cells affect milk production. Therefore, ensuring adequate mammary epithelial cells is expected to enhance milk production. This study is devoted to studying the effects of kisspeptin-10 (Kp-10), a peptide hormone composed of 10 amino acids, on bovine mammary epithelial cell (bMEC) proliferation and exploring the underlying mechanism of its action. bMECs were treated with various concentrations of Kp-10 (1, 10, 100, and 1,000 nM), and 100 nM Kp-10 promoted the proliferation of the bMECs. Kp-10 promoted the cell cycle transition from G1 to the S and G2 phases, increased the protein levels of Cyclin D1 and Cyclin D3, and reduced the expression levels of the p21 gene. This study also showed that inhibition of G protein-coupled receptor 54 (GPR54), AKT, mTOR, and ERK1/2 reduced the proliferation of the bMECs that had been induced by Kp-10. In addition, Kp-10 decreased the complexes formed by Rb and E2F1 and increased the expression levels of the E2F1 target genes. These results indicate that Kp-10 promotes bMEC proliferation by activating GPR54 and its downstream signaling pathways.     

A zinc-dependent nuclear endonuclease is responsible for DNA laddering during salt-induced programmed cell death in root tip cells of rice

DNA laddering is one of the biochemical processes characteristic of programmed cell death (PCD) both in animals and plants. However, the mechanism of DNA laddering varies in different species, even in different tissues of one organism. In the present study, we used root tip cells of rice, which have been induced by NaCl stress to undergo PCD, to analyze the endonuclease activities of cytoplasmic and nuclear extracts. Two endonucleases, a cytoplasmic of 20kDa (OsCyt20) and a nuclear of 37kDa (OsNuc37), were identified as PCD related. Our results indicated that OsCyt20 is a Ca(2+)/Mg(2+)-dependent nuclease, which is most active at neutral pH, and that OsNuc37 is Zn(2+)-dependent, with a pH optimum of 4.5-6. Both nucleases were induced at the early stage of PCD (2h salt treatment) and exhibited the highest activity approximately 4h after exposure to NaCl, paralleling with the occurrence of DNA laddering. In vitro assays of endonuclease activities further revealed that OsNuc37, a glycoprotein localized in the nucleus, is the executor for DNA laddering. The different effects of both endonucleases on DNA degradation during salt-induced PCD are discussed.     

Protective Role of Deoxyschizandrin and Schisantherin A against Myocardial Ischemia–Reperfusion Injury in Rats

Background

Our previous studies suggested that deoxyschizandrin (DSD) and schisantherin A (STA) may have cardioprotective effects, but information in this regard is lacking. Therefore, we explored the protective role of DSD and STA in myocardial ischemia–reperfusion (I/R) injury.

Methodology/Principal Findings

Anesthetized male rats were treated once with DSD and STA (each 40 µmol/kg) through the tail vein after 45 min of ischemia, followed by 2-h reperfusion. Cardiac function, infarct size, biochemical markers, histopathology and apoptosis were measured and mRNA expression of gp91^phox in myocardial tissue assessed by RT-PCR. Neonatal rat cardiomyocytes were pretreated with DSD and STA and then damaged by H₂O₂. Cell apoptosis was tested by a flow cytometric assay. Compared with the I/R group: (i) DSD and STA could significantly reduce the abnormalities of LVSP, LVEDP, ±dp/dt_max and arrhythmias, thereby showing their protective roles in cardiac function; (ii) DSD and STA could significantly attenuate the infarct size and MDA release while increasing SOD activity, suggesting a role in reducing myocardial injury; (iii) tissue morphology and myocardial textual analysis revealed that DSD and STA mitigated changes in myocardial histopathology; (iv) DSD and STA decreased apoptosis (33.56±2.58% to 10.28±2.80% and 10.98±1.99%, respectively) and caspase-3 activity in the myocardium (0.62±0.02 OD/mg to 0.38±0.02 OD/mg and 0.32±0.02 OD/mg, respectively), showing their protective effects upon cardiomyocytes; and (v) DSD and STA had similar protective effects on I/R injury as those seen with the positive control metoprolol. In vitro, DSD and STA could significantly decrease the apoptosis of neonatal cardiomyocytes.

Conclusions/Significance

These data suggest that DSD and STA can protect against myocardial I/R injury. The underlining mechanism may be related to their role in inhibiting cardiomyocyte apoptosis.     

The complete mitochondrial genome of Neobenedenia melleni (Platyhelminthes: Monogenea): mitochondrial gene content,arrangement and composition compared with two Benedenia species

The complete mitochondrial (mt) genome sequences of Neobenedenia melleni were determined and compared with those of Benedenia seriolae and B. hoshinai. This circular genome comprises 13,270 bp and includes all 36 typical mt genes found in flatworms. Total AT content of N. melleni is 75.9 %. ATG is the most common start codon, while nad4L is initiated by GTG. All protein-coding genes are predicted to terminate with TAG and TAA. N. melleni has the trnR with a TCG anticodon, which is the same to B. seriolae but different from B. hoshinai (ACG). The mt gene arrangement of N. melleni is similar to that of B. seriolae and B. hoshinai with the exception of three translocations (trnF, trnT and trnG). The overlapped region between nad4L and nad4 was found in the N. melleni mt genome, which was also reported for the published Gyrodactylus species, but it was not found in those of B. seriolae and B. hoshinai, which are non-coding regions instead. The present study provides useful molecular characters for species or strain identification and systematic studies of this parasite.     

PI3P phosphatase activity is required for autophagosome maturation and autolysosome formation

Autophagosome formation is promoted by the PI3 kinase complex and negatively regulated by myotubularin phosphatases, indicating that regulation of local phosphatidylinositol 3‐phosphate (PtdIns3P) levels is important for this early phase of autophagy. Here, we show that the Caenorhabditis elegans myotubularin phosphatase MTM‐3 catalyzes PtdIns3P turnover late in autophagy. MTM‐3 acts downstream of the ATG‐2/EPG‐6 complex and upstream of EPG‐5 to promote autophagosome maturation into autolysosomes. MTM‐3 is recruited to autophagosomes by PtdIns3P, and loss of MTM‐3 causes increased autophagic association of ATG‐18 in a PtdIns3P‐dependent manner. Our data reveal critical roles of PtdIns3P turnover in autophagosome maturation and/or autolysosome formation.     

The Mediating Effects of Burnout on the Relationship between Anxiety Symptoms and Occupational Stress among Community Healthcare Workers in China: A Cross-Sectional Study

Background

Several occupational stress studies of healthcare workers have predicted a high prevalence of anxiety symptoms, which can affect their quality of life and the care that they provide. However, few studies have been conducted among community healthcare workers in China. We attempted to explore whether burnout mediates the association between occupational stress and anxiety symptoms.

Methods

A cross-sectional survey was completed in Liaoning Province, China from November to December 2012. A total of 1,752 healthcare workers from 52 Community Health Centers participated in this study, and all participants were given self-administered questionnaires. These questionnaires addressed the following aspects: the Zung Self-Rating Anxiety Scale, the Chinese version of the effort-reward imbalance scale and the Maslach Burnout Inventory–General Survey. Finally, the study included 1,243 effective respondents (effective response rate, 70.95%). Hierarchical linear regression analysis, performed with SPSS 17.0, was used to estimate the effect of burnout.

Results

The prevalence of anxiety symptoms among the community healthcare workers was 38.0%. After adjusting for demographic characteristics, the effort–reward ratio and overcommitment positively predicted anxiety symptoms. Meanwhile, the effort–reward ratio and overcommitment were positively related to the emotional exhaustion and cynicism subscales of burnout. In addition, the emotional exhaustion and cynicism subscales were positively related to anxiety symptoms. Thus, there is a link between burnout, occupational stress and anxiety symptoms.

Conclusions

Burnout mediates the effect of occupational stress on anxiety symptoms. To effectively reduce the impact of occupational stress on anxiety symptoms, burnout management should be considered.     

Overexpression of monocarboxylate anion transporter 1 and 4 in T24-induced cancer-associated fibroblasts regulates the progression of bladder cancer cells in a 3D microfluidic device

Stromal fibroblasts are essential for tumor proliferation and invasion. Here we presented a 3-dimensional (3D) microfluidic co-culture device to reconstruct an in vivo-like tumor microenvironment for investigation of the interactions of cancer-associated fibroblasts (CAFs) and bladder cancer cells. With this device, we verified that the cytokines secreted by bladder cancer cells T24 effectively transform the fibroblasts into CAFs. Compared to fibroblasts, the CAFs, which undergo the aerobic glycolysis, showed higher ability to produce lactate and provide energy for bladder cancer cell proliferation and invasion. We also demonstrated that this kind of tumor-promoting effect was associated with the upregulation of monocarboxylate anion transporter 1 (MCT1) and MCT4 expression in CAFs. We concluded that MCT1 and MCT4 are involved in bladder cancer cell proliferation and invasiveness. Moreover, this 3D microfluidic co-culture device allows for the assay to characterize various cellular events in a single device sequentially, facilitating a better understanding of the interactions among heterotypic cells in a sophisticated microenvironment.     

Atomic‐Scale Spacing between Copper Facets for the Electrochemical Reduction of Carbon Dioxide

Copper (Cu) offers a means for producing value‐added fuels through the electrochemical reduction of carbon dioxide (CO₂), i.e., the CO₂ reduction reaction (CO₂RR), but designing Cu catalysts with significant Faradaic efficiency to C₂₊ products remains as a great challenge. This work demonstrates that the high activity and selectivity of Cu to C₂₊ products can be achieved by atomic‐scale spacings between two facets of Cu particles. These spacings are created by lithiating CuO_x particles, removing lithium oxides formed, and electrochemically reducing CuO_x to metallic Cu. Also, the range of spacing (d_s) is confirmed via the 3D tomographs using the Cs‐corrected scanning transmission electron microscopy (3D tomo‐STEM), and the operando X‐ray absorption spectra show that oxidized Cu reduces to the metallic state during the CO₂RR. Moreover, control of d_s to 5–6 Å allows a current density exceeding that of unmodified CuO_x nanoparticles by about 12 folds and a Faradaic efficiency of ≈80% to C₂₊. Density functional theory calculations support that d_s of 5–6 Å maximizes the binding energies of CO₂ reduction intermediates and promotes C–C coupling reactions. Consequently, this study suggests that control of d_s can be used to realize the high activity and C₂₊ product selectivity for the CO₂RR.     

Identification and expression analysis of miRNAs from nitrogen-fixing soybean nodules

miRNAs are ～21 nt non-coding RNAs and play important roles in plant development and response to stress. Symbiotic nitrogen fixation (SNF) is agronomically important for reducing the need of nitrogen fertilizers. The soybean root nodule is the place where SNF takes place. To identify miRNAs that are possibly involved in nitrogen fixation in soybean functional nitrogen-fixing nodules, a small library of RNAs was constructed from the functional nodules harvested 28 days after inoculation with rhizobium. Thirty-two small RNA sequences were identified as belonging to 11 miRNA families. Eight miRNAs are conserved across plant species, twenty are specific to soybean, and the four remaining miRNAs are novel. Expression analysis revealed that miRNAs were differentially expressed in the different tissues. Combinatorial miRNA target prediction identified genes that are involved in multiple biological processes. The results suggest that miRNAs play critical and diverse roles in SNF, nutrient acquisition, and plant development.