The transcription factor RppA regulates chlorophyll and carotenoid biosynthesis to improve photoprotection in cyanobacteria.

Chlorophyll is an essential photosynthetic pigment but also a strong photosensitizer. Excessive free chlorophyll and its precursors can cause oxidative damage to photosynthetic organisms. Cyanobacteria are the oldest oxygenic photosynthetic organisms and the ancestors of the chloroplast. Owing to their complex habitats, cyanobacteria require precise regulation of chlorophyll synthesis to respond to environmental factors, especially changes in light. Chlorophyll synthase, encoded by chlG, is the enzyme catalyzing the final step of chlorophyll biosynthesis, which is closely related to photosynthesis biogenesis. However, the transcriptional regulation on chlG remains unclear. Here, the transcription factor, regulator of photosynthesis and photopigment-related gene expression A (RppA) was identified to bind to the chlG promoter by screening a yeast one-hybrid library in the cyanobacterium Synechocystis sp. PCC 6803. The rppA knock-out mutant showed a phenotype of slow growth and severe oxidative damage under dark-light transition conditions. The up-regulated transcriptional expression of chlG was significantly higher and more chlorophyll and its precursors accumulated in the rppA knock-out mutant than those in the wild-type strain during the transition from darkness to light, indicating RppA represses the expression of chlG in Synechocystis. Meanwhile, RppA could synchronously promote the transcription of carotenoids biosynthesis-related genes to enhance carotenoids synthesis during the dark-light transition. These results reveal synergistic regulation of chlorophyll and carotenoids biosynthesis in cyanobacteria in response to frequent dark-light transitions, which slows down chlorophyll biosynthesis while promoting carotenoids biosynthesis to avoid oxidative damage caused by excessive reactive oxygen species accumulation.

Targeting inhibition of TCTP could inhibit proliferation and induce apoptosis in AML cells.

Translationally controlled tumor protein (TCTP) is a highly conserved multifunctional protein, which participates in many important physiological processes. Recently, the roles of TCTP in cell proliferation and apoptosis, especially its close relationship with various tumors, have attracted widespread attention. In this study, we found that the protein level of TCTP was significantly reduced in acute promyelocytic leukemia cell line NB4 transfected with retinoic acid-induced gene G (RIG-G). The RIG-G was found in our previous work as a key mediator of anti-proliferative activity in retinoid/interferon-related pathways. Here, we tried to further explore the function of TCTP in the development of acute myeloid leukemia (AML) from different levels. Our results showed that inhibiting TCTP expression could attenuate AML cells proliferation and induce apoptosis both in AML cell lines and in xenograft of NOD-SCID mice. In addition, either compared with patients in complete remission or non-leukemia patients, we detected that the expression of TCTP was generally high in the fresh bone marrow of AML patients, suggesting that there was a certain correlation between TCTP and AML disease progression. Taken together, our study revealed the role of TCTP in AML development, and provided a potential target for AML treatment.

Hypothetical chloroplast reading frame 51 encodes a photosystem I assembly factor in cyanobacteria.

Hypothetical chloroplast open reading frames (ycfs) are putative genes in the plastid genomes of photosynthetic eukaryotes. Many ycfs are also conserved in the genomes of cyanobacteria, the presumptive ancestors of present-day chloroplasts. The functions of many ycfs are still unknown. Here, we generated knock-out mutants for ycf51 (sll1702) in the cyanobacterium Synechocystis sp. PCC 6803. The mutants showed reduced photoautotrophic growth due to impaired electron transport between photosystem II (PSII) and PSI. This phenotype results from greatly reduced PSI content in the ycf51 mutant. The ycf51 disruption had little effect on the transcription of genes encoding photosynthetic complex components and the stabilization of the PSI complex. In vitro and in vivo analyses demonstrated that Ycf51 cooperates with PSI assembly factor Ycf3 to mediate PSI assembly. Furthermore, Ycf51 interacts with the PSI subunit PsaC. Together with its specific localization in the thylakoid membrane and the stromal exposure of its hydrophilic region, our data suggest that Ycf51 is involved in PSI complex assembly. Ycf51 is conserved in all sequenced cyanobacteria, including the earliest branching cyanobacteria of the Gloeobacter genus, and is also present in the plastid genomes of glaucophytes. However, Ycf51 has been lost from other photosynthetic eukaryotic lineages. Thus, Ycf51 is a PSI assembly factor that has been functionally replaced during the evolution of oxygenic photosynthetic eukaryotes.

Two Structurally Similar Co5 Cluster-Based Metal-Organic Frameworks Containing Open Metal Sites for Efficient C2H2/CO2 Separation.

To reasonably design and synthesize metal-organic frameworks (MOFs) with high stability and excellent adsorption/separation performance, the pore configuration and functional sites are very important. Here, we report two structurally similar cluster-based MOFs using a pyridine-modified low-symmetry ligand [H4L = 2,6-bis(2',5'-dicarboxyphenyl)pyridine], [(NH2Me2)2][Co5(L)2(OCH3)2(µ3-OH)2·2DMF]·2DMF·2H2O (1) and [Co5(L)2(µ3-OH)2(H2O)2]·2H2O·4DMF (2). The structures of 1 and 2 are built from Co5 clusters, which have one-dimensional open channels, but their microporous environments are different due to the different ways in which ligands bind to the metals. Both MOFs have extremely high chemical stabilities over a wide pH range (2-12). The two MOFs have similar adsorption capacities of C2H2 (144.0 cm3 g-1 for 1 and 141.3 cm3 g-1 for 2), but 1 has a higher C2H2/CO2 selectivity of 3.5 under ambient conditions. The difference in gas adsorption and separation between the two MOFs has been compared by a breakthrough experiment and theoretical calculation, and the influence of the microporous environment on the gas adsorption and separation performance of MOFs has been further studied.

DNASE1L3 inhibits proliferation, invasion and metastasis of hepatocellular carcinoma by interacting with ß-catenin to promote its ubiquitin degradation pathway.

As a member of the deoxyribonuclease 1 family, DNASE1L3 plays a significant role both inside and outside the cell. However, the role of DNASE1L3 in hepatocellular carcinoma (HCC) and its molecular basis remains to be further investigated. In this study, we report that DNASE1L3 is downregulated in clinical HCC samples and evaluate the relationship between its expression and HCC clinical features. In vivo and in vitro experiments showed that DNASE1L3 negatively regulates the proliferation, invasion and metastasis of HCC cells. Mechanistic studies showed that DNASE1L3 recruits components of the cytoplasmic ß-catenin destruction complex (GSK-3ß and Axin), promotes the ubiquitination degradation of ß-catenin, and inhibits its nuclear transfer, thus, decreasing c-Myc, P21 and P27 level. Ultimately, cell cycle and EMT signals are restrained. In general, this study provides new insight into the mechanism for HCC and suggests that DNASE1L3 can become a considerable target for HCC.

The small molecule chemical compound cinobufotalin attenuates resistance to DDP by inducing ENKUR expression to suppress MYH9-mediated c-Myc deubiquitination in lung adenocarcinoma.

The small molecule chemical compound cinobufotalin (CB) is reported to be a potential antitumour drug that increases cisplatin (DDP) sensitivity in nasopharyngeal carcinoma. In this study, we first found that CB decreased DDP resistance, migration and invasion in lung adenocarcinoma (LUAD). Mechanistic studies showed that CB induced ENKUR expression by suppressing PI3K/AKT signalling to downregulate c-Jun, a negative transcription factor of ENKUR. Furthermore, ENKUR was shown to function as a tumour suppressor by binding to ß-catenin to decrease c-Jun expression, thus suppressing MYH9 transcription. Interestingly, MYH9 is a binding protein of ENKUR. The Enkurin domain of ENKUR binds to MYH9, and the Myosin_tail of MYH9 binds to ENKUR. Downregulation of MYH9 reduced the recruitment of the deubiquitinase USP7, leading to increased c-Myc ubiquitination and degradation, decreased c-Myc nuclear translocation, and inactivation of epithelial-mesenchymal transition (EMT) signalling, thus attenuating DDP resistance. Our data demonstrated that CB is a promising antitumour drug and may be a candidate chemotherapeutic drug for LUAD patients.

Ultrahigh conductivity of graphene nanoribbons doped with ordered nitrogen.

Graphene is an attractive candidate for developing high conductivity materials (HCMs) owing to an extraordinary charge mobility. While graphene itself is a semi-metal with an inherently low carrier density, and methods used for increasing carrier density normally also cause a marked decrease in charge mobility. Here, we report that ordered nitrogen doping can induce a pronounced increase in carrier density but does not harm the high charge mobility of graphene nanoribbons (GNRs), giving rise to an unprecedented ultrahigh conductivity in the system. Our first-principles calculations for orderly N-doped GNRs (referred to as C5N-GNRs) show that N-doping causes a significant shift-up of the Fermi level (ΔE F), resulting in the presence of multiple partially-filled energy bands (PFEDs) that primarily increase the carrier density of system. Notably, the PFEDs are delocalized well with integral and quantized transmissions, suggesting a negligible effect from N-doping on the charge mobility. Moreover, the PFEDs can cross the E F multiple times as the ribbon widens, causing the conductivity to increase monotonically and reach ultrahigh values (>15G 0) in sub-5 nm wide ribbons with either armchair or zigzag edges. Furthermore, a simple linear relationship between the doing concentration and the ΔE F was obtained, which provides a robust means for controlling the conductivity of C5N-GNRs. Our findings should be useful for understanding the effect of ordered atomic doping on the conductivity of graphene and may open new avenues for realizing graphene-based HCMs.

Arginine methylation of SIRT7 couples glucose sensing with mitochondria biogenesis.

Sirtuins (SIRTs) are a class of lysine deacylases that regulate cellular metabolism and energy homeostasis. Although sirtuins have been proposed to function in nutrient sensing and signaling, the underlying mechanism remains elusive. SIRT7, a histone H3K18-specific deacetylase, epigenetically controls mitochondria biogenesis, ribosomal biosynthesis, and DNA repair. Here, we report that SIRT7 is methylated at arginine 388 (R388), which inhibits its H3K18 deacetylase activity. Protein arginine methyltransferase 6 (PRMT6) directly interacts with and methylates SIRT7 at R388 in vitro and in vivo R388 methylation suppresses the H3K18 deacetylase activity of SIRT7 without modulating its subcellular localization. PRMT6-induced H3K18 hyperacetylation at SIRT7-target gene promoter epigenetically promotes mitochondria biogenesis and maintains mitochondria respiration. Moreover, high glucose enhances R388 methylation in mouse fibroblasts and liver tissue. PRMT6 signals glucose availability to SIRT7 in an AMPK-dependent manner. AMPK induces R388 hypomethylation by disrupting the association between PRMT6 and SIRT7. Together, PRMT6-induced arginine methylation of SIRT7 coordinates glucose availability with mitochondria biogenesis to maintain energy homeostasis. Our study uncovers the regulatory role of SIRT7 arginine methylation in glucose sensing and mitochondria biogenesis.

CARM1 Methylates GAPDH to Regulate Glucose Metabolism and Is Suppressed in Liver Cancer.

Increased aerobic glycolysis is a hallmark of cancer metabolism. How cancer cells coordinate glucose metabolism with extracellular glucose levels remains largely unknown. Here, we report that coactivator-associated arginine methyltransferase 1 (CARM1 or PRMT4) signals glucose availability to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and suppresses glycolysis in liver cancer cells. CARM1 methylates GAPDH at arginine 234 (R234), inhibiting its catalytic activity. Glucose starvation leads to CARM1 upregulation, further inducing R234 hypermethylation and GAPDH inhibition. The re-expression of wild-type GAPDH, but not of its methylation-mimetic mutant, sustains glycolytic levels. CARM1 inhibition increases glycolytic flux and glycolysis. R234 methylation delays tumor cell proliferation in vitro and in vivo. Compared with normal tissues, R234 is hypomethylated in malignant clinical hepatocellular carcinoma samples. Notably, R234 methylation positively correlates with CARM1 expression in these liver cancer samples. Our findings thus reveal that CARM1-mediated GAPDH methylation is a key regulatory mechanism of glucose metabolism in liver cancer.

Sertraline exerts its antitumor functions through both apoptosis and autophagy pathways in acute myeloid leukemia cells.

It has been found that sertraline, a widely used antidepressant drug, possessed antitumor roles in a variety of cancers including liver cancer, colorectal cancer and lymphoma. In this study, we provided evidences that sertraline had potent antiproliferative activity not only in acute myeloid leukemia (AML) cell lines but also in the fresh leukemia cells from AML patients, and could induce cell death through both apoptosis and autophagy pathways. Moreover, we found that inhibiting autophagy pathway could partially attenuate sertraline-induced apoptosis and cell growth inhibition, indicating that sertraline-induced autophagy process could facilitate AML cell apoptosis to some degree. However, blocking apoptosis pathway seemed no obvious effects on sertraline-caused autophagy as well as cell growth inhibition. Our results suggested a potential application value of sertraline in the treatment of AML patients, furnishing some perspectives for novel therapeutic strategies in leukemia.

[Effect of Wenyang Decoction on the Differentiation of CD34+ Progenitor Cells in Occupational Asthma Model Rats].

OBJECTIVE: To study the effect of Wenyang Decoction (WD) on the differentiation of CD34+ progenitor cells of occupational asthma (OA) model rats. METHODS: Fifty healthy male SD rats were randomly divided into five groups, i.e., the model group, the blank control group,the WD group,the Western medicine group,the combined group, 10 in each group. Prednisone suspension (10 mg/kg) was administered to rats in the Western medicine group by gastrogavage. WD (20 g/kg) was administered to rats in the WD group by gastrogavage. Prednisone suspension plus WD was administered to rats in the combined group by gastrogavage. Normal saline was administered to rats in the model group and the blank control group by gastrogavage. The general condition of rats was observed. Expression levels of peripheral blood IL-5 and eotaxin, eosinophils (EOS), CD34+, CC chemokine receptor 3 (CCR3+) in bone marrow suspension were detected by ELISA, Wirght-Giemsa, and flow cytometry, respectively. RESULTS: Compared with the blank control group,expression levels of IL-5 and eotaxin in peripheral blood were significantly higher (P < 0.01), and the count of EOS and CD34+ cells, as well as CD34+ /CCR3+ significantly increased (P < 0.01) in the model group. Compared with the model group, expression levels of IL-5 and eotaxin, the count of EOS, CD34+ cells, CD34+ / CCR3+ were lowered in three treated groups (P < 0.01). Compared with the Western medicine group, the count of EOS and CD34+ / CCR3+ decreased in the combined group (P < 0.01). The count of EOS was significantly lower in the combined group than in the WD group (P < 0.01). CONCLUSION: WD could reduce levels of in vivo inflammatory factors, and restrain the differentiation and recruitment of EOS,thereby alleviating the differentiation of CD34 progenitor cells to EOS.

[Experimental Study on Apoptosis of Kasumi-1 Cells Induced by Sertraline and Its Molecular Mechanism].

OBJECTIVE: To investigate the biological effects of sertraline, one of psychotropic drugs, on actue myeloid leukemia cell line Kasumi-1. METHODS: Cells were treated by different concentrations of sertraline for different times. The effects of sertraline were evaluated by cell growth, cell morphology, cell cycle distribution and markers of cell apoptosis, respectively. Western blot was used to detect the expression change of related proteins. RESULTS: Sertraline could inhibit cell proliferation and induce apoptosis. After treatment with 15 µmol/L and 20 µmol/L sertraline for 24 h, the inhibitory rate of Kasumi-1 cell proliferation was (19.00 ± 7.37)% and (47.90 ± 11.19)%, respectively. Meanwhile, compared with the control group, the percentage of Annexin V positive cells in Kasumi-1 cells treated with sertraline for 24 h raised obviously from (9.71 ± 2.12)% to (20.54 ± 2.52)% and (45.37 ± 7.88)% (P < 0.01), respectively. The cells were arrested in G0/G1 and G2/M phase. In addition, it was found that sertraline could also down-regulate the level of translationally controlled tumor protein (TCTP) in Kasumi-1 cells. CONCLUSION: Sertraline can significantly induce the apoptosis of Kasumi-1 cells, that probably is associated with the down-regulation of TCTP protein expression.

Role of the cerebrospinal fluid-contacting nucleus in the descending inhibition of spinal pain transmission.

The brainstem is well recognized as a critical site for integrating descending modulatory systems that both inhibit and facilitate pain at the level of the spinal cord. The cerebrospinal fluid-contacting nucleus (CSF-contacting nucleus) distributes and localizes in the ventral periaqueductal central gray of the brainstem. Although emerging lines of evidence suggest that the CSF-contacting nucleus may be closely linked to transduction and regulation of pain signals, the definitive role of the CSF-contacting nucleus in pain modulation remains poorly understood. In the present study, we determined the role of the CSF-contacting nucleus in rat nocifensive behaviors after persistent pain by targeted ablation of the CSF-contacting nucleus in the brainstem using the cholera toxin subunit B-saporin (CB-SAP), a cytotoxin coupled to cholera toxin subunit B. Compared with CB/SAP, CB-SAP induced complete ablation of the CSF-contacting nucleus, and the CB-SAP-treated rats showed hypersensitivity in responses to acute nociceptive stimulation, and exacerbated spontaneous nocifensive responses induced by formalin, thermal hyperalgesia and mechanical allodynia induced by plantar incision. Furthermore, immunohistochemical experiments showed that the CSF-contacting nucleus was a cluster of 5-HT-containing neurons in the brainstem, and the spinal projection of serotonergic axons originating from the CSF-contacting nucleus constituted the descending 5-HT pathway to the spinal cord. CB-SAP induced significant downregulation of 5-HT in the spinal dorsal horn, and intrathecal injection of 5-HT significantly reversed hypersensitivity in responses to acute nociceptive stimulation in the CB-SAP-treated rats. These results indicate that the CSF-contacting nucleus 5-HT pathway is an important component of the endogenous descending inhibitory system in the control of spinal nociceptive transmission.

[Expressions of CD34 and CD117 in human hepatocellular carcinomas and the clinical significance].

To study the expressions of CD34 and CD117 in the tissues of hepatocelluar carcinoma (HCC) and to explore the relationship with clinical pathology and it's evaluation on the prognosis of HCC patients. The expressions of CD34 and CD117 were examined by two-step methods of PV-9000 of immunohistochemistry in 55 HCC cases, 10 liver cirrhotic specimens and 6 normal liver specimens. Clinical-pathological data, tumor recurrent rate and survival rate after hepatectomy were recorded and analyzed with Fisher's Exact Test, Pearson X2 Test, Kaplan-Meier, Log-Rank Test and Cox Regression. The positive expression of CD34 was found in 65.4% of HCC, 20% of cirrhostic liver specimens and 16.7% of normal liver specimens, respectively. Significant differences found among the three groups, and the CD34 expression was significantly associated with vessel embolus (X2 = 4.000, P = 0.046) and the histological grades (X2 = 11.008, P = 0.001). The positive expression of CD117 was 47.3%, 10% and 0% in HCC, cirrhotic liver specimens and normal liver tissues, respectively, and statistical differences esxisted among the three groups. The CD117 expression was dramatically related to the histological grades (X2 = 5.115, P = 0.024) and clinical stages (X2 = 15.459, P = 0.000). Median disease free survival time after hepatectomy was significantly shorter in the group with positive-expression of CD34 (X2 = 4.105, P = 0.043) and CD117 (X2 = 28.023, P = 0.000) than the negative-expressed groups, respectively. Multivariate analysis showed that CD117 expression status, serum AFP levels and the size of tumor were independently prognostic factors for HCC patients. Tthe results demonstrated that CD34 and CD117 might play an important role in liver carcinogenesis and the progression of HCC, and they might potentially serve as markers for HCC prognosis.

[The effect of temperature on the PL spectra of high power LED].

Two kinds of 1 W white high power light emitting diode (LED) were made by packaging blue chips from Taiwan and US. The chips were coated by the same phosphor and transparent silica gel. Optical properties of the two kinds of LEDs were investigated in the temperature range of 15-75 degrees C and at the current of 350 mA. The results show that temperature badly affects the optical parameters such as peak wavelength, radiant flux, color temperature and so on. After analyzing the PL spectrum, the relationship between temperature and LED performance was found. The reasons for optical parameters vs. temperature were theoretically analyzed. Some suggestions were given to reduce the influence of temperature on power LED.

[The property of white powder LED with different ratio of phosphor].

White powder light emitting diodes (LED) with different color temperature were made by using different ratio of yellow to orange silicate phosphor. When the ratio of yellow to orange phosphor was less than 7, the peak wavelength of yellow light in spectra was about 570 nm and the wavelength was about 590 nm as the ratio was greater than 7. With the color temperature increasing, the color rendering index and the luminous efficiency increased at the beginning and then decreased. And color temperature of 5 521 K is the optimal value. The reason was the ineffective excitation of blue light due to higher concentration of phosphor and excess red light in spectra. In contrast, blue light was not excited effectively and red light in spectra was little when the color temperature was higher than 5 521 K. The luminous efficiency was decreased, and the decreased magnitude was inconsistency with the testing temperature from 10 to 80 degrees C. This suggests that, besides Auger recombination, the decrease in excitation efficiency of yellow and orange phosphors is different as the temperature rises and orange phosphor's temperature characteristic is superior to that of yellow phosphor.

Numerical simulation of air flow through a biofilter with heterogeneous porous media.

Based on the ideal biofilter model, numerical simulation using lattice Boltzmann method is carried out to investigate the effect of Darcy number and porosity on removal efficiency of low headloss biofilter. The generalized Navier-Stokes model (Brinkman-Forchheimer-extended Darcy model) is applied making several assumptions. It is found that the Darcy number has determinant influence on the removal efficiency, and the effect of porosity on removal efficiency is very weak at lower Darcy numbers but very strong at higher Darcy numbers. It was found there was strong evidence of flow heterogeneity in the biofilter (Chitwood, D.E., Devinny, J.S., Reynolds Jr., F.E., 1999. Evaluation of a two-stage biofilter for treatment of POTW waste air. Environ. Prog. 18, 212-221). In this study we have found the biofilter performance can be improved by adjusting local Darcy number of the porous media in the biofilter.

[Study on the self-assembly ability of expressed capsid protein of rabbit haemorrhagic disease virus that fused with foreign epitope at the N-terminus].

The RHDV capsid protein (VP60) gene was first subcloned into the transfer plasmid pBLUEBACHIS2B located downstream of a 6 * HIS tag, then the recombinant transfer plasmid DNA were cotransfected Sf 9 cells with Bac-N-Blue DNA and purified for cloned recombinant baculovirus by plaque assay. The expression of fused-VP60 gene was analyzed by SDS-PAGE and Western blot. A specific 69 kD protein band was obtained. Observed under electron micrography, the recombinant baculovirus expressed VP60 protein assembled into viruslike particles which were morphologically and antigenically similar to native RHD virus but did not package RNA. The close-to-native conformation of the VLPs was also supported by the haemagglutination test, in which recombinant VLPs, like RHDV, agglutinated human blood type O erythrocytes.

[Expression of capsid gene of Chinese isolate of rabbit hemorrhagic disease virus in Pichia pastoris].

The capsid protein (VP60) gene of RHDV was subcloned into the Pichia expressin vector pPICZ B to express the VP60 protein intracellularly. The recombinant plasmid was initially transformed into a E. coli strain TOP10 F'. After verification of the construct by sequencing, the recombinant plasmid was linearized by Sac I in the 5' AOX1 region and then transformed into Pichia pastoris strain GS115 using the Pichia EasyComp Kit. After selecting and verifing for the insertion of VP60 gene in the genome, two clones of Pichia transformants were select for expression test. The recombinant clones were first inoculate with BMGY in baffled flask at 28-30 degrees C in a shaking incubator (250-300 r/min) until culture reaches an OD600 = 2-6, then resuspend the cell pellet to an OD6oo of 1.0 in BMMY medium to induce expression for 5 days by methanol at a concentration of 0.5% in a 1 liter baffled flask covered with 2 layers of sterile gauze. Collect the cell pellets and break it by acid-washed 0.5 mm glass beads. The expression of recombinant Pichia strains was detected by SDS-PAGE and Western analysis with a polyclonal serum which showed a specific protein band of 60kD. Theses results indicates that the recombinant VP60 produced in Pichia was antigenically similar to the viral polypeptide. Electron microscopic observation of the recombinant Pichia-derived protein revealed the presence of virus-like particles similar in size and appearance to native virus capsids. In the haemagglutination test, the recombinant VLPs, like the native RHDV, also agglutinated human blood type O erythrocytes and could be inhibited by the anti-RHDV polyclonal serum.