Effect of dietary concentrate level on digestibility of nutrients in each region of the gastrointestinal tract and rumen fermentation in goats.

This study evaluated the effects of high concentrate diets (HCD) on the rumen fermentation and the digestibility of nutrients in different sites of the gastrointestinal tract (GIT) in goats. Four goats were used in a crossover design. The goats were fitted with a ruminal cannula and flexible T-cannulae proximal duodenum and terminal ileum. Treatments were as follows: low concentrate group (LCG) and high concentrate group (HCG). Duodenal flow and forestomach digestibility of starch were significantly higher in the HCG than those in the LCG (p < 0.05); There was no significant difference in ileum flow and digestibility of starch in the small intestine, large intestine and total GIT (p > 0.05). The digestibility of crude protein (CP) in the forestomach was significantly higher in the HCG than in the LCG (p < 0.05); the flow of the duodenum and ileum of CP, and the CP digestibility of the small intestine, large intestine and total GIT were not significantly different between groups (p > 0.05). The duodenal and ileal flow of neutral detergent fiber (NDF), the NDF digestibility of the different segments and total GIT were not significantly different between groups (p > 0.05). Compared to the LCG, the ruminal pH of the HCG was significantly lower (p < 0.05). The HCG concentrations of microbial crude protein, ammonia nitrogen and isovaleric acid were significantly higher (p < 0.05) than the LCG. The foam strength, foam production and viscosity of the rumen fluid in the HCG were higher than the LCG (p < 0.01). These results showed that when the goats were fed with HCD, the digestibility of nutrients was not significantly impaired, but the risk of frothy rumen bloat increased. ImplicationsDue to a serious shortage of high-quality roughage in China, producers commonly used a high-concentrate diet in ruminants, which can improve animal production performance.Gastrointestinal digestive function plays a vital role in the absorption of nutrients and the healthy growth of animals.Therefore, this research evaluated the digestibility of various nutrients in different segments of the gastrointestinal tract (GIT) under HCD feeding by using three-site cannula goats as experimental animals.The results indicated that the GIT of goats could fully digest nutrients such as starch and protein under HCD feeding conditions.

[Preparation and Characterization of Manganese and Fluorine Co-Modified Hydroxyapatite Composite Coating].

Titanium and titanium alloys have been widely used as orthopedic, dental implants and cardiovascular stents owing to their superior physical properties. However, titanium surface is inherently bio-inert, thus could not form efficient osseointegration with surrounding bone tissue. Therefore, to improve the surface property of titanium implant is significantly important in clinical application. Manganese and fluorine co-doped hydroxyapatite (FMnHAP) coatings were prepared on titanium substrate by electrochemical deposition technique. The as-prepared coatings were examined by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) tests. The results indicated that the FMnHAP coatings take the morphology of nanoscale-villous-like, the composite coating becomes more compact. The FTIR test indicated that the symmetry of bending vibration modes of hydroxyl changed, simulated body fluid immersion test proved that the FMnHAP coatings had induce carbonate-apatite formation, indicating that the composite coating possess excellent biocompatibility. In the electrochemical corrosion testing, the FMnHAP coatings showed stronger corrosion resistance than pure Ti.

Strophalloside induces apoptosis of SGC-7901 cells through the mitochondrion-dependent caspase-3 pathway.

Cardenolides with special chemical structures have been considered as effective anti-cancer drugs in clinic trials. Strophalloside is a cardenolide we recently isolated from Antiaris toxicaria obtained from Hainan, China. The aim of this study was to investigate the possible anticancer effects induced by strophalloside and the underlying molecular mechanism. Gastric carcinoma SGC-7901 cells were treated with strophalloside at various concentrations for different times, and resulting cell viability was determined by the MTT assay, and the motility and invasion of tumor cells were assessed by the Transwell chamber assay. Apoptosis were measured by Annexin V-FITC/PI and Hoechst staining. The changes of mitochondrial transmembrane potential were examined by a JC-1 kit. The expressions of pro-apoptotic protein cytochrome c, caspase-3 and caspase-9 were detected by western blotting analysis. The results showed that strophalloside was capable of reducing cell viability, inhibiting cell growth, and suppressing cell migration and invasion in a time- and dose-dependent manner. Mitochondrial membrane potential declined and the concentration of cytochrome c increased in cytoplasm and caspase-3 and caspase-9 were cleaved into activated states, suggesting that cytochrome c was released from the mitochondrion to cytoplasm and finally activated the caspase-dependent apoptosis pathway. Our results indicate that strophalloside is a potential anticancer drug.

[Surface Enhanced Raman Spectroscopic Studies on the Coupling Effect of Multilayer Au@SiO2 Film].

The SiO2 shell with the thickness of 4 nm was attached onto high surface enhanced Raman spectroscopy (SERS) active Au core nanoparticles to obtain Au@SiO2 core shell nanoparticles by the hydrolysis of sodium silicate solution with the boiling water bath. The inert shell of SiO2 isolated the direct interaction of Au nanoparticles and probe molecules. The stable, compact and uniform monolayer nanoparticles film was self assembled at water/oil interface, and one to six monolayers film was transferred to Si wafer as SERS substrates through layer by layer technique. The relationship between the SERS activities and layers of the monolayer nanoparticles film on Si surface was investigated. The SERS mapping was developed to determine the layers of the Au@SiO2 film. The coupling effect among the Au@SiO2 films was explored by changing the adsorption location of the probe on the multilayer films. The result revealed that the monolayer film was a favourable candidate with high-quality performances for the SERS application. The SERS signal was distributed on the surface with high uniformity at the same monolayer film, and it was enhanced in the intensity with the increase in film layers. It reached the maximun intensity as the film was over five layers. It indicated that the SERS signal was contributed mainly by the first five monolayers. The probe molecules were immobilized onto the first monolayer nanoparticles film, and the SERS signal from the probe approached to the maximum as the second monolayer covered the probe modified first nanoparticles film. It was dominated by the coupling effect ("hot spots") of the adjacent layers. The SERS signal decreased in intensity when the third layer was transferred onto the second layer, and it disappeared after the fouth layer was covered, mainly duo to the shield of the nanoparticles film to the incident laser and Raman signal. The preliminary results provided guidance for fabricating optimal SERS substrates.

Hepatitis B surface antigen inhibits MICA and MICB expression via induction of cellular miRNAs in hepatocellular carcinoma cells.

Hepatitis B surface antigen (HBsAg) seropositivity is an important risk factor for hepatocellular carcinoma (HCC), and HBsAg-transgenic mice have been reported to spontaneously develop HCC. The major histocompatibility complex class I-related molecules A and B (MICA and MICB) are NKG2D ligands that play important roles in tumor immune surveillance. In the present study, we found that HBsAg overexpression in HepG2 cells led to upregulation of 133 and downregulation of 9 microRNAs (miRNAs). Interestingly, several HBsAg-induced miRNAs repressed the expression of MICA and MICB via targeting their 3'-untranslated regions. In addition, the expression of MICA and MICB was significantly reduced upon HBsAg overexpression, which was partially restored by inhibiting the activities of HBsAg-induced miRNAs. Moreover, HBsAg-overexpressing HCC cells exhibited reduced sensitivity to natural killer cell-mediated cytolysis. Taken together, our data suggest that HBsAg supresses the expression of MICA and MICB via induction of cellular miRNAs, thereby preventing NKG2D-mediated elimination of HCC cells.

MicroRNA-581 promotes hepatitis B virus surface antigen expression by targeting Dicer and EDEM1.

Hepatitis B virus surface antigen (HBsAg) is an important risk factor for hepatocellular carcinoma (HCC) and is downregulated during hepatocarcinogenesis. MicroRNAs (miRNAs) are frequently deregulated in HCC tissues. However, whether the deregulation of certain miRNAs in HCC has an impact on HBsAg expression remains unclear. We found here that microRNA-581 (miR-581), which is deregulated during hepatocarcinogenesis, promoted HBsAg expression. Additionally, miR-581 targeted Dicer and endoplasmic reticulum degradation-enhancing alpha-mannosidase-like protein 1 (EDEM1) and repressed their expression. Although Dicer cannot process HBV transcripts, Dicer knockdown led to increased HBsAg secretion, most likely due to a reduction in the levels of Dicer-processed 7SL RNA fragments. Moreover, Dicer-processed 7SL RNA fragments partially inhibited the ability of miR-581 to stimulate HBsAg expression. Furthermore, we found that forced EDEM1 expression inhibited miR-581-mediated induction of HBsAg. Finally, transfection of miR-581 into HepG2.2.15 cells promoted cell proliferation and led to upregulation of genes involved in development, cell proliferation and protein secretion. Altogether, we conclude that miR-581 promotes HBsAg expression by targeting Dicer and EDEM1. Our findings suggest that downregulation of miR-581 during hepatocarcinogenesis may lead to a reduction in HBsAg expression and impede HCC development.

[Study on chemical constituents from rhizome of Rabdosia flavida].

OBJECTIVE: To study the chemical constituents from the rhizome of Rabdosia flavida. METHODS: The compounds were isolated and purified by various chromatographic methods, and their structures were elucidated on the basis of spectral data and physicochemical properties. RESULTS: Ten compounds were obtained from ethyl acetate fraction of the 70% acetone extract of Rabdosia flavida rhizome and identified as ferruginol (1), dehydrocostuslactone (2), taraxasterol (3), oleic acid (4), ursolic cid (5), coniferyl aldehyde (6), oleanolic acid (7), 6,12, 15-trihydroxy-5, 8,11, 13-abietetra-7-one (8), 5α, 8α-epidioxyergosta-6,22-dien-3ß-ol (9), and daucosterol (10). CONCLUSION: All the compounds are isolated from Rabdosia flavida for the first time.

Magnetic separation of heavy metal ions and evaluation based on surface-enhanced Raman spectroscopy: copper(II) ions as a case study.

A new approach was developed for the magnetic separation of copper(II) ions with easy operation and high efficiency. p-Mercaptobenzoic acid served as the modified tag of Fe2O3@Au nanoparticles both for the chelation ligand and Raman reporter. Through the chelation between the copper(II) ions and carboxyl groups on the gold shell, the Fe2O3@Au nanoparticles aggregated to form networks that were enriched and separated from the solution by a magnet. A significant decrease in the concentration of copper(II) ions in the supernatant solution was observed. An extremely sensitive method based on surface-enhanced Raman spectroscopy was employed to detect free copper(II) ions that remained after the magnetic separation, and thus to evaluate the separation efficiency. The results indicated the intensities of the surface-enhanced Raman spectroscopy bands from p-mercaptobenzoic acid were dependent on the concentration of copper(II) ions, and the concentration was decreased by several orders of magnitude after the magnetic separation. The present protocol effectively decreased the total amount of heavy metal ions in the solution. This approach opens a potential application in the magnetic separation and highly sensitive detection of heavy metal ions.

Dynamic three-sided matching model for personnel-robot-position matching problem in intelligent environments.

In recent years, intelligent robots have facilitated intelligent production, and a new type of problem (personnel-robot-position matching (PRPM)) has been encountered in personnel-position matching (PPM). In this study, a dynamic three-sided matching model is proposed to solve the PRPM problem in an intelligent production line based on man-machine collaboration. The first issue considered is setting the dynamic reference point, which is addressed in the information evaluation phase by proposing a method for setting the dynamic reference point based on the prospect theory. Another important issue involves multistage preference information integration, wherein a probability density function and a value function are introduced. Considering the attenuation of preference information in a time series, the attenuation index model is introduced to calculate the satisfaction matrix. Furthermore, a dynamic three-sided matching model is established. Additionally, a multi-objective decision-making model is established to optimize the matching of multiple sides (personnel, intelligent robots, and positions). Subsequently, the model is transformed into a single objective model using the triangular balance principle, which is introduced to obtain the final optimisation results in this modelling process. A case study is presented to illustrate the practicality of the dynamic three-sided matching model in intelligent environments. The results indicate that this model can solve the PRPM problem in an intelligent production line.

MicroRNA-34a inhibits migration and invasion of colon cancer cells via targeting to Fra-1.

MicroRNA-34a (miR-34a), a transcriptional target of p53, is a well-known tumor suppressor gene. Here, we identified Fra-1 as a new target of miR-34a and demonstrated that miR-34a inhibits Fra-1 expression at both protein and messenger RNA levels. In addition, we found that p53 indirectly regulates Fra-1 expression via a miR-34a-dependant manner in colon cancer cells. Overexpression of miR-34a strongly inhibited colon cancer cell migration and invasion, which can be partially rescued by forced expression of the Fra-1 transcript lacking the 3'-untranslated region. The expression of matrix metalloproteinase (MMP)-1 and MMP-9, two enzymes involved in cell migration and invasion, was decreased in miR-34a-transfected cells, and this can be rescued by Fra-1 overexpression. Moreover, we found that miR-34a was downregulated in 25 of 40 (62.5%) colon cancer tissues, as compared with the adjacent normal colon tissues and that the expression of miR-34a was correlated with the DNA-binding activity of p53. Unexpectedly, the DNA-binding activity of p53 was not inversely correlated with Fra-1 expression, and a significant statistical inverse correlation between miR-34a and Fra-1 expression was only observed in 14 of 40 (35%) colon cancer tissues. Taken together, our in vitro data suggest that p53 regulates Fra-1 expression, and eventually cell migration/invasion, via a miR-34a-dependent manner. However, in vivo data indicate that the p53-miR-34a pathway is not the major regulator of Fra-1 expression in human colon cancer tissues.

A Prognostic Survival Model of Pancreatic Adenocarcinoma Based on Metabolism-Related Gene Expression.

Accurately predicting the survival prospects of patients suffering from pancreatic adenocarcinoma (PAAD) is challenging. In this study, we analyzed RNA matrices of 182 subjects with PAAD based on public datasets obtained from The Cancer Genome Atlas (TCGA) as training datasets and those of 63 subjects obtained from the Gene Expression Omnibus (GEO) database as the validation dataset. Genes regulating the metabolism of PAAD cells correlated with survival were identified. Furthermore, LASSO Cox regression analyses were conducted to identify six genes (XDH, MBOAT2, PTGES, AK4, PAICS, and CKB) to create a metabolic risk score. The proposed scoring framework attained the robust predictive performance, with 2-year survival areas under the curve (AUCs) of 0.61 in the training cohort and 0.66 in the validation cohort. Compared with the subjects in the low-risk cohort, subjects in the high-risk training cohort presented a worse survival outcome. The metabolic risk score increased the accuracy of survival prediction in patients suffering from PAAD.

[Fabrication of reproducible surface enhanced Raman scattering substrate and its application].

Gold nanoparticles were homogeneously coated with silica using the silane coupling agent (3-aminopropyl)-trimethoxysilane to functionalize the gold surface and sodium silicate solution as the precursor of silica. The shell thickness could be well controlled by changing the amount of sodium silicate, reaction temperature and time. The Au@SiO2 core-shell nanoparticles with a suitable silica shell thickness exhibited optimal SERS activity and were self-assembled onto an ITO substrate in order to get a stable and reproducible SERS substrate. The conditions for preparing SERS substrates can be optimized by investigating the relationship between the intensity of SERS signals and the thickness of silica shell. The reproducible SERS measurements were performed by using 1,4-BDT and 4,4'-bipyridine as probe molecules. Within a certain concentration range, the linear relationship between the SERS intensities and the logarithm of concentration was obtained. The results revealed that the Au@SiO2 substrate assembled on ITO surface could be developed as a reproducible substrate for the quantitative analysis.

Neuroprotective effects of novel compound Tozan on cognition, neurogenesis and apoptosis in diabetes.

BACKGROUND: Cognitive impairment is a serious complication of diabetes that manifests as an impairment of spatial memory and learning ability. Its pathogenesis is unclear, and effective therapeutic drugs are very limited. Our group designed and synthesized a novel compound named 3-p-tolyl-9H-xanthen-9-one (Tozan). In this study, we sought to investigate the effects and mechanism of Tozan on diabetic cognitive impairment. METHODS: Methylglyoxal (MG)-induced SH-SY5Y cells and streptozotocin (STZ)-induced type 1 diabetic mice were treated with Tozan. Methyl thiazolul tetrazolium (MTT) and lactate dehydrogenase (LDH) were used to test cytotoxicity. Morris water maze (MWM) and Y-maze tests were used to evaluate cognitive function. Immunofluorescence and western blot analyses were used to evaluate neurogenesis, apoptosis, and signal transduction pathway-related proteins. In addition, Lentivirus (LV)-estrogen receptor beta (ERß)-ribonucleic acid interference (RNAi) was used to knockdown the ERß gene in SH-SY5Y cells. RESULTS: We found that Tozan ameliorated MG-induced cytotoxicity in SH-SY5Y cells, improved cognitive dysfunction in STZ-induced type 1 diabetic mice, increased neurogenesis, and prevented apoptotic responses in vitro and in vivo. Importantly, Tozan (2, 4, and 8 mg/kg) mediated phosphatidylinositol-3-kinase and protein kinase B cAMP-response element binding protein (PI3K/Akt-CREB) signaling by activating membrane ERß, and a high dose of Tozan (8 mg/kg) mediated CREB signaling by activating nuclear ERß in the hippocampus. Notably, Tozan did not have an anti-apoptosis and regeneration protective role in ERß gene knockdown cells. CONCLUSIONS: Our study demonstrates Tozan's contributions to and role in cognition, neurogenesis, and apoptosis in diabetes, and lays an experimental foundation for the development of new anti-diabetic cognitive impairment drugs.

Rosiglitazone-induced myocardial protection against ischaemia-reperfusion injury is mediated via a phosphatidylinositol 3-kinase/Akt-dependent pathway.

1. Rosiglitazone is widely used in the treatment of Type 2 diabetes. However, in recent years it has become evident that the therapeutic effects of peroxisome proliferator-activated receptor gamma ligands reach far beyond their use as insulin sensitizers. Recently, the ability of rosiglitazone pretreatment to induce cardioprotection following ischaemia-reperfusion (I/R) has been well documented; however, the protective mechanisms have not been elucidated. In the present study, examined the role of the phosphatidylinositol 3-kinase (PI3-K)/Akt signalling pathway in rosiglitazone cardioprotection following I/R injury. 2. Mice were pretreated with 3 mg/kg per day rosiglitazone for 14 days before hearts were subjected to ischaemia (30 min) and reperfusion (2 h). Wortmannin (1.4 mg/kg, i.p.), an inhibitor of PI3-K, was administered 10 min prior to myocardial I/R. Then, activation of the PI3-K/Akt/glycogen synthase kinase (GSK)-3alpha signalling pathway was examined. The effects of PI3-K inhibition on rosiglitazone-induced cardioprotection were also evaluated. 3. Compared with control rats, the ratio of infarct size to ischaemic area (area at risk) and the occurrence of sustained ventricular fibrillation in rosiglitazone-pretreated rats was significantly reduced (P < 0.05). Rosiglitazone pretreatment attenuated cardiac apoptosis, as assessed by ELISA to determine cardiomyocyte DNA fragmentation. Rosiglitazone pretreatment significantly increased levels of phosphorylated (p-) Akt and p-GSK-3alpha in the rat myocardium. Pharmacological inhibition of PI3-K by wortmannin markedly abolished the cardioprotection induced by rosiglitazone. 4. These results indicate that rosiglitazone-induced cardioprotection in I/R injury is mediated via a PI3-K/Akt/GSK-3alpha-dependent pathway. The data also suggest that modulation of PI3-K/Akt/GSK-3alpha-dependent signalling pathways may be a viable strategy to reduce myocardial I/R injury.

[Mechanism underlying photocatalyzed degradation of methyl orange by layered black phosphorus]. / é»‘ç£·çº³ç±³ç‰‡å ‰å‚¬åŒ–ç”²åŸºæ©™é™è§£æœºç†.

A large amount of azo dye wastewater is discharged into the environment, with serious risks to ecosystems and human health. Therefore, the development of treatment technology of azo dye wastewater was of practical significance. Photocatalytic methods showed promising application prospects due to easy to implement and effective. In this study, layered black phosphorus nanosheet (LBP) was used as a catalyst through liquid phase exfoliation method. Methyl orange (MO) was employed as a model azo dye to investigate the catalytic mechanism of LBP. The dominant transient species involved in the photocatalytic reaction was probed by quenching and fluorescence probe experiments. Degradation pathways of MO were proposed according to degradation products identified by the liquid chromatography-mass spectrometry. The results showed that degradation rate (kobs) of MO at acidic condition (pH=3.0) or alkaline condition (pH=11.0) was higher than that at neutral condition (pH=7.0). Degradation pathways of MO included that the azo bond was attacked by hydroxyl radicals (·OH) photogenerated by the LBP, and the intermediate products were further oxidized by ·OH to produce N, N-dimethyl-4-(2-p-phenylmethylhydrazine) aniline, 2-(dimethylamino)-5-((4(dimethylamino) phenyl) diazenyl) phenol and N, N-dimethyl-4-nitroaniline.

Purification, characterization, and functional groups of an extracellular aflatoxin M1 -detoxifizyme from Bacillus pumilus E-1-1-1.

The experiment was conducted to purify high activity extracellular enzymes, which were produced by a strain that we previously screened was able to degrade aflatoxin effectively, and speculate the functional groups of the enzyme associated with degradation. An extracellular aflatoxin-detoxifizyme (DAFE) from Bacillus pumilus E-1-1-1 was purified through a process including ammonium sulfate precipitation, ultrafiltration, Sephadex chromatography, and ion exchange chromatography. The molecular mass of the enzyme assessed by SDS-PAGE was found to be approximately 58 kDa. The optimum reaction temperature and pH for the purified enzyme were 45°C and pH 7, respectively. The enzyme showed temperature stability of up to 60°C. Ba2+ , Ca2+ Na+ , Mn2+ , EDTA, and ß-mercaptoethanol showed inhibitory effects on the enzyme activity. Mg2+ , Fe3+ , Zn2+ and K+ were the activators of enzymes. This enzyme was composed of at least 15 kinds of amino acids. Lysine, tryptophan, and histidine residues were necessary and major functional groups to maintain enzyme activity, disulfide bonds were observed, serine residues had little effect on the enzyme activity, so it was not the necessary group to reflect the enzyme activity, and arginine had no effect on enzyme activity.

[Ischemic postconditioning attenuates ischemia/reperfusion injury in isolated hypertrophied rat heart].

OBJECTIVE: To explore the effects of ischemic postconditioning on ischemia/reperfusion injury in isolated hypertrophied rat heart and investigate the signal transduction pathway changes induced by ischemia postconditioning. METHODS: Cardiac hypertrophy was induced in rats by abdominal aortic banding, and isolated hypertrophied rat heart ischemia/reperfusion model was made by Langendorff technique to evaluate the effects of ischemia postconditioning on left ventricular systole pressure, coronary artery flow, creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) release, myocardial infarction size, and the level of myocardial phospho-protein kinase B/Akt (Ser473), phospho-glycogen synthase kinase-3beta (Ser9). Following groups were studied (n = 12 each group): IR, 30 min ischemia (I)/60 min Reperfusion (R); Post: 30 min ischemia, 6 circles of 10 s I/10 s R followed by 60 min R; Post Wort: 30 min ischemia, 6 circles of 10 s I/10 s R, wortmannin (10(-7) mol/L) followed by 60 min R; Wort: 30 min ischemia, wortmannin (10(-7) mol/L) followed by 60 min R. RESULTS: Left ventricular systolic pressure and coronary artery flow were significantly increased, myocardial infarction size and the release of CPK, LDH significantly reduced in Post group compared to that in IR group. Phospho-protein kinase B/Akt (Ser473) and phospho-glycogen synthase kinase-3beta (Ser9) levels were also significantly higher in Post group than that in IR group. Phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin prevented the increase of phospho-protein kinase B/Akt (Ser473) and phospho-glycogen synthase kinase-3beta (Ser9) induced by ischemic postconditioning, but only partly abolished the cardioprotection of ischemic postconditioning. CONCLUSION: Ischemic postconditioning attenuates ischemia/reperfusion injury in isolated hypertrophied rat heart. The cardioprotective effects of ischemic postconditioning were partly mediated through PI3K/Akt/GSK-3beta signaling pathway.

Energetic salts based on an oxygen-containing cation: 2,4-diamino-1,3,5-triazine-6-one.

A family of energetic salts with high thermal stability and low impact sensitivity based on an oxygen-containing cation, 2,4-diamino-1,3,5-triazine-6-one, were synthesized and fully characterized by IR and multinuclear ((1)H, (13)C) NMR spectroscopy, elemental analysis, and differential scanning calorimetry. Insights into their sensitivities towards impact, friction, and electrostatics were gained by submitting the materials to standard tests. The structures of 2,4-diamino-1,3,5-triazine-6-one nitrate, 2,4-diamino-1,3,5-triazine-6-one sulfate, 2,4-diamino-1,3,5-triazine-6-one perchlorate, 2,4-diamino-1,3,5-triazine-6-one 5-nitrotetrazolate were determined by single-crystal X-ray diffraction; their densities are 1.691, 1.776, 1.854, and 1.636 g cm(-3), respectively. Most of the salts decompose at temperatures over 180 °C; in particular, the salts 2,4-diamino-1,3,5-triazine-6-one nitrate and 2,4-diamino-1,3,5-triazine-6-one perchlorate, which decompose at 303.3 and 336.4 °C, respectively, are fairly stable. Furthermore, most of the salts exhibit excellent impact sensitivities (>40 J), friction sensitivities (>360 N), and are insensitive to electrostatics. The measured densities of these energetic salts range from 1.64 to 2.01 g cm(-3) . The detonation pressure values calculated for these salts range from 14.6 to 29.2 GPa, and the detonation velocities range from 6536 to 8275 m s(-1) ; these values make the salts potential candidates for thermally stable and insensitive energetic materials.

Decreased dicer expression enhances SRP-mediated protein targeting.

We have shown that Dicer processes 7SL RNA into different fragments ranging from ∼20 to more than 200 nucleotides. Here we addressed the molecular functions of these 7SL RNA fragments and found that some of them functioned as dominant-negative regulators of the full-length 7SL RNA, interfering with signal recognition particle (SRP) complex formation. Transfection of these 7SL RNA fragments inhibited the expression of cell surface glycoproteins, the targeting of a reporter protein to the endoplasmic reticulum, and the secretion of secreted alkaline phosphatase. These results suggest that some Dicer-processed 7SL RNA fragments interfered with SRP-mediated protein targeting. Moreover, we showed that Dicer knockdown enhanced SRP-mediated protein targeting and that transfection of a mixture of the 7SL RNA fragments partially restored this effect. Our data indicate that Dicer can fine-tune the efficiency of SRP-mediated protein targeting via processing a proportion of 7SL RNA into fragments of different lengths.

Dicer-dependent biogenesis of small RNAs derived from 7SL RNA.

It has been reported that decreased Dicer expression leads to Alu RNAs accumulation in human retinal pigmented epithelium cells, and Dicer may process the endogenous SINE/B1 RNAs (the rodent equivalent of the primate Alu RNAs) into small interfering RNAs (siRNAs). In this study, we aimed to address whether Dicer can process Alu RNAs and their common ancestor, 7SL RNA. Using Solexa sequencing technology, we showed that Alu-derived small RNAs accounted for 0.6% of the total cellular small RNAs in HepG2.2.15 cells, and the abundance decreased when Dicer was knocked down. However, Alu-derived small RNAs showed different characteristics from miRNAs and siRNAs, the classic Dicer-processed products. Interestingly, we found that small RNAs derived from 7SL RNA accounted for 3.1% of the total cellular small RNAs in the control cells, and the abundance dropped about 3.4 folds in Dicer knockdown cells. Dicer-dependent biogenesis of 7SL RNA-derived small RNAs was validated by northern blotting. In vitro cleavage assay using the recombinant human Dicer protein also showed that synthetic 7SL RNA was processed by Dicer into fragments of different lengths. Further functional analysis suggested that 7SL RNA-derived small RNAs do not function like miRNAs, neither do they regulate the expression of 7SL RNA. In conclusion, the current study demonstrated that Dicer can process 7SL RNA, however, the biological significance remains to be elucidated.