Lanthipeptides from the Same Core Sequence: Characterization of a Class II Lanthipeptide Synthetase from Microcystis aeruginosa NIES-88.

Class II lanthipeptide synthetases (LanMs) are relatively promiscuous to core peptide variations. Previous studies have shown that different LanMs catalyze identical reactions on the same core sequence fused to their respective cognate leaders. We characterized a new LanM enzyme from Microcystis aeruginosa NIES-88, MalM, and demonstrated that MalM and ProcM exhibited disparate dehydration and cyclization patterns on identical core peptides. Our study provided new insights into the regioselectivity of LanMs and showcased an appropriate strategy for lanthipeptide structural diversity engineering.

Protective effect of hyperoside against hydrogen peroxide-induced dysfunction and oxidative stress in osteoblastic MC3T3-E1 cells.

Oxidative stress can induce apoptosis and decrease activities of osteoblasts. Hyperoside (HYP) is a potent antioxidant derived from Chinese herb. This study aims to evaluate the protective effects provided by HYP to osteoblastic MC3T3-E1 cells. MC3T3-E1 cells were pre-treated with HYP for 24 h before being treated with 0.3 mM hydrogen peroxide (H2O2) for 24 h. Cell viability, flow cytometric analysis and mRNA expression of alkaline phosphatase (ALP), collagen I (COL-I) and osteocalcin (OCN) in MC3T3-E1 cells were examined. We next examined apoptosis-related and mitogen-activated protein kinase (MAPK) related proteins in HYP and H2O2 groups. HYP over the dose of 40 µmol/L could obviously increase the MC3T3-E1 cell viability at 24 h and 48 h (p < .05). HYP significantly (p < .05) increased mRNA expression of ALP, COL-I and OCN than H2O2 group. Moreover, HYP decreased the apoptosis rate and apoptosis-related proteins that induced by H2O2. In addition, HYP decreased the production of phosphorylated Jun N-terminal kinase (JNK) and p38 levels of osteoblastic MC3T3-E1 cells induced by H2O2. These results demonstrated that the protective effect provided by HYP to osteoblastic MC3T3-E1 cells was mediated, at least in part, via inhibition of MAPK signalling pathway and oxidative damage of the cells.

The efficacy and potential mechanism of cnidium lactone to inhibit osteoclast differentiation.

Cnidium lactone is effective in the maintenance of bone mass in various osteoporosis models; however, the precise molecular mechanisms are not understood. In this study, we investigated the effects and underlying mechanisms of action of cnidium lactone on receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis. Cnidium lactone dose-dependently inhibited osteoclast differentiation and formation, decreased the bone-resorbing activity of osteoclasts, and downregulated the expression of osteoclast differentiation marker genes. Cnidium lactone treatment considerably reduced RANKL-induced p38 MAPK and PI3K-Akt signal activity in RAW264.7 cells. The cnidium lactone-induced osteoclastogenesis was significantly attenuated by inhibition of p38 and PI3K through pretreatment with SB203580 and LY294002, respectively. Furthermore, cnidium lactone inhibited the expression of c-Fos and NFATc-1 with dose-dependently and enhanced by SB203580 and LY294002. In conclusion, cnidium lactone inhibits osteoclast differentiation through p38 MAPK and PI3K-Akt signalling pathway/c-Fos/NFATc1 signalling pathway.

[Estimation of Winter Wheat Photosynthesized Carbon Distribution and Allocation Belowground via 13C Pulse-labeling].

Evaluating the allocation of carbon (C) photosynthesized by winter wheat belowground is essential for C sequestration in soil and crop production. During the four growth stages of winter wheat, i. e., tillering, elongation, anthesis, and grain-filling, the method of 13CO2 pulse-labeling for the wheat was adopted. Destructive samplings were undertaken at 28 d after each labeling and the total C and 13C contents of shoots, roots, soil, and rhizosphere respiration were determined. Results showed that the majority of the fixed 13C was recovered in the aboveground (straw and grain), ranging from 51.6% to 90.8% in all growth stages. The allocation of 13C photosynthesized belowground (roots, soil, and rhizosphere respiration) decreased as the wheat growth advanced, while the 13C transferred to the aboveground increased. Of the total 13C input belowground, 22.9%-65.3% was respired by the rhizosphere, 24.3%-59.3% remained in the roots, and 10.4%-17.8% was incorporated into the soil organic carbon by rhizodeposition. Respired 13C within the last 2 d of the whole chase period (28 d) only accounted for 0.7%-2.7% of the total respired 13C, indicating that 28 days were long enough to ensure a complete distribution of photosynthesized C within all the wheat and soil pools. For the whole growth season of winter wheat, the photosynthesized C allocated aboveground, to roots, soil organic carbon, and rhizosphere respiration was 78.5%, 6.0%, 3.1%, and 12.4% of the net assimilated C, respectively. Based on local wheat production, the total C transferred belowground was quantified as 1.72 t·hm-2, with 0.99 t·hm-2 respired as rhizosphere respiration, 0.48 t·hm-2 retained in roots, and 0.25 t·hm-2 incorporated into soil organic carbon.

MicroRNA-645 promotes metastasis of osteosarcoma via targeting tumor suppressor NM23 nucleoside diphosphate kinase 2.

Osteosarcoma is the most common non-hematological primary bony malignancy in children and young adults with tumor metastasis being a common event at diagnosis. Understanding the pathogenesis of metastatic osteosarcoma may help identify potential therapeutic targets. In this study, we found that the level of microRNA-645 (miR-645) in osteosarcoma tumor tissues was significantly increased compared with their paired non-tumorous tissues, and was associated with histologic grade, TNM staging, lymph metastasis and distant metastasis. Knockdown of miR-645 caused a remarkable inhibition of migration of osteosarcoma U2OS cells. Furthermore, miR-645 inhibited NME2 (nucleoside diphosphate kinase 2) expression through directly binding to its 3' untranslated region. In human osteosarcoma tissues, we also found that NME2 was significantly decreased in tumor tissues, and its level was negatively correlated with miR-645. In addition, silencing NME2 attenuated the decreased cell migration by knockdown of miR-645, suggesting that it was involved in the miR-645 induced cell migration of osteosarcoma cells. Taken together, we found that miR-645 was up-regulated in osteosarcoma tissues and could promote osteosarcoma cell migration through directly inhibiting the tumor suppressor NME2. Our data provide novel insight into the role of miR-645 in osteosarcoma and indicate that miR-645 might be a potential therapeutic target of osteosarcoma.

TIMP-1 suppressed by miR-138 participates in endoplasmic reticulum stress-induced osteoblast apoptosis in osteoporosis.

The aim of this study was to investigate the role of miR-138 in osteoporosis and its underlying mechanism. Hydrogen peroxide (H2O2) was used to induce osteoporotic injury of osteoblasts. The cell viability and apoptosis of MC3T3-E1 cells was assessed using MTT assay and flow cytometry, respectively. The cell transfection was carried out to modulate the expression levels of miR-138 and TIMP-1 in MC3T3-E1 cells. Luciferase reporter gene assay was performed to determine the interaction between miR-138 and TIMP-1 3'UTR. In the present study, H2O2 inhibited osteoblasts growth and induced intracellular endoplasmic reticulum (ER) stress accompanied by high expression of miR-138. We also confirmed that miR-138 promoted osteoblasts apoptosis in vitro and in vivo. MiR-138 was further indicated to inhibit osteoblast survival via negative regulating TIMP-1 expression. Moreover, the downregulated TIMP-1 also mediated the ER stress-induced apoptosis of osteoblasts. We confirmed that miR-138 and ER stress were induced in osteoporosis and then promoted the apoptosis of osteoblasts, at least in part, through TIMP-1.

Phenotypic changes of Schwann cells on the proximal stump of injured peripheral nerve during repair using small gap conduit tube.

Dedifferentiation of Schwann cells is an important feature of the response to peripheral nerve injury and specific negative myelination regulators are considered to have a major role in this process. However, most experiments have focused on the distal nerve stump, where the Notch signaling pathway is strongly associated with Schwann cell dedifferentiation and repair of the nerve. We observed the phenotypic changes of Schwann cells and changes of active Notch signaling on the proximal stump during peripheral nerve repair using small gap conduit tubulization. Eighty rats, with right sciatic nerve section of 4 mm, were randomly assigned to conduit bridging group and control group (epineurium suture). Glial fibrillary acidic protein expression, in myelinating Schwann cells on the proximal stump, began to up-regulate at 1 day after injury and was still evident at 5 days. Compared with the control group, Notch1 mRNA was expressed at a higher level in the conduit bridging group during the first week on the proximal stump. Hes1 mRNA levels in the conduit bridging group significantly increased compared with the control group at 3, 5, 7 and 14 days post-surgery. The change of the Notch intracellular domain shared a similar trend as Hes1 mRNA expression. Our results confirmed that phenotypic changes of Schwann cells occurred in the proximal stump. The differences in these changes between the conduit tubulization and epineurium suture groups correlate with changes in Notch signaling. This suggests that active Notch signaling might be a key mechanism during the early stage of neural regeneration in the proximal nerve stump.

Crystal structure of poly[[aqua-(µ-2,3-di-hydro-thieno[3,4-b][1,4]dioxine-5,7-di-carboxyl-ato-κ2O5:O7)[µ-di(pyridin-4-yl)sulfane-κ2N:N']zinc] 0.26-hydrate].

The crystal structure of the title polymer, {[Zn(C8H4O6S)(C10H8N2S)(H2O)]·0.26H2O} n , is characterized by a layered arrangement parallel to the ab plane. The zinc cation is five-coordinated in a slightly distorted trigonal-bipyramidal coordination environment defined by two pyridine ligands, two carboxyl-ate groups of two thio-phene di-carboxyl-ate ligands, and by one water mol-ecule. The ethyl-ene bridge in the dioxine ligand is disordered over two sets of sites [occupancy ratio 0.624 (9):0.376 (9)]. Several hydrogen-bonding inter-actions of the types O-H⋯O, C-H⋯O, C-H⋯S and C-H⋯N ensure the cohesion within the crystal structure.

[Effects of Different Agricultural Practices on Soil Carbon Pool in North China Plain].

North China Plain is an important region of grain production.Soil fertility and grain production in this region are significantly influenced by the levels of soil carbon and nitrogen.In order to explore the effects of agricultural practices on the levels of soil carbon and nitrogen,a long-term field experiment was started in 1999 in Quzhou County,Hebei Province.Four treatments,including following nature (F),tillage without straw (N),no tillage with crushed straw incorporation (S),and tillage with crushed straw incorporation (TS),were chosen to collect soil samples at the layers of 0-20 cm and 20-40 cm in 2013.Soil organic carbon (SOC),soil inorganic carbon (SIC),total carbon (TC),total nitrogen (TN),δ13CSOC,δ13CSIC and δ15 N were analyzed.The results indicated that compared with F,SOC stocks of N,S and TS decreased by 21.6%,12.3% and 3.4% in the 0-20 cm soil layer,but the changes of SIC stocks were not significant.In the 20-40 cm soil layer,the changes of the SOC stocks were not significant,but the SIC stocks increased by 4.1%(N),7.3%(S) and 5.0%(TS) compared to F,respectively.Major contribution of SIC increase was the pedogenic inorganic carbonate (PIC),which increased by 97%-261% in the farmland soil.In the soil layer of 0-20 cm,the values of δ15N,δ13CSIC and δ13CSOC in the farmland treatments were higher than those of F,meanwhile,the values of δ13 CSOC were significantly higher than that of F.In the soil layer of 20-40 cm,the values of δ15N and δ13CSIC were lower than those of F,but the value of δ13CSOC showed the opposite trend.In North China Plain,lithogenic inorganic carbonate (LIC) of farmland soil decomposed and PIC increased by the soil-crop system,which provided CO2 for the formation of PIC,and straw returning was an effective agricultural practice to restore the soil carbon decreased by tillage.There should be more long-term monitoring and studies for the impacts of crop straw incorporation and tillage on SOC and SIC,especially for soil in deeper layers.

Role of recombinant plasmid pEGFP-N1-IGF-1 transfection in alleviating osteoporosis in ovariectomized rats.

Decreased levels of serum insulin-like growth factor-1 (IGF-1) have been proven to cause osteoporosis. Gene transfer of IGF-1 offers an attractive technology to treat skeletal metabolic disorders including osteoporosis, but the viral vectors are limited by their high antigenicity and immune response. Our purpose was to investigate the expression of a non-invasive vector, recombinant plasmid enhanced green fluorescent protein-N1 (pEGFP-N1) that transferred IGF-1 gene into ovariectomized (OVX) rats in vivo and evaluate the effect of this therapy on osteoporosis. OVX or sham operations were performed in 60 female, 7-month-old unmated SD rats. 12 weeks after OVX operation, the vectors were transfected to the 10-month-old rats and experimental data were detected from 48 h to 7 week after transfection. Our results showed that remarkable expression of fluorescence and serum IGF-1 was observed in the rats transfected by recombinant plasmids, indicating that IGF-1 gene was successfully transferred to OVX rats by injecting the vector through hydrodynamic method via the tail vein. The bone metabolism index including serum alkaline phosphatase, the histomorphometric parameters of lumbar vertebra including trabecular area percentage, trabecular thickness, trabecular number and trabecular separation, and the bone mineral density (BMD) and biomechanical parameters of lumbar vertebra including BMD, maximum condensing force, crushing strength in OVX rats transfected by pEGFP-N1-IGF-1 were improved remarkably compared with OVX+pEGFP-N1 rats, indicating that the transfection of recombinant plasmid pEGFP-N1-IGF-1 played a significant role in alleviating osteoporosis in rats induced by OVX. This encouraged a potential approach of IGF-1 gene therapy to the treatment of osteoporosis.

[Impact of land use change and cultivation measures on soil organic carbon (SOC) and its 13C values].

In Quzhou County, Hebei Province where now intensive farming system is operated, original grassland and farming land under different tillage, crop straw return and fertilization measures were studied using isotope carbon for the analysis of the impact on soil organic carbon (SOC) properties. The research indicated that after change into farmland (34 years), SOC is significantly reduced and for 1 m of soil layer, the scope of reduction is from 13.3%-35% and this decrease happens in 0-40 cm of soil layer. After 8 years of fertilization, SOC can be increased at 0.83 g x kg(-1). No-tillage can significantly increase the SOC especially in 0-10 cm but plough will increase the SOC at 10-15 cm and 15-20 cm. Change of delta13 C of SOC due to land use change mainly happens in 0-20 cm, where input of organic materials from maize stored. In soil layer of 0-5 cm, only maximum 18% of SOC is from crop residues and in 15-20 cm, this percentage is about 5%.

2,2-Bis(1H-indol-3-yl)indolin-3-one.

In the title mol-ecule, C(24)H(17)N(3)O, the mean plane of the indolone ring forms dihedral angles of 112.0 (1) and 103.1 (1)° with the planes of the two indole rings. The dihedral angle between the mean planes of the two indole rings is 63.5 (1)°. In the crystal structure, mol-ecules are linked via inter-molecular N-H⋯O hydrogen bonds, forming a two-dimensional network parallel to the ab plane.

[GIS-based analysis of spatio-temporal variability of groundwater nitrate concentration in high-yield region in North China Plain].

Nitrate pollution in groundwater is very widespread in intensive agricultural region. 394 samples from phreatic water wells and 283 samples from confined water wells were collected across Huantai County at the same season of 2002 and 2007, which is representative of high-yield region of North China Plain. The NO3- -N concentration was determined. Geostatistics combined with GIS technique were used to analyze the spatio-temporal variability of groundwater nitrate concentration. The average nitrate concentrations in phreatic water were 8.08 mg x L(-1) and 14.68 mg x L(-1) in 2002 and 2007 respectively, and that in confined water were 3.87 mg x L(-1) and 7.19 mg x L(-1) respectively. The spatial correlation distances of nitrate concentrations in confined water for both periods were greater than that in phreatic water. The mapping showed that the areas of phreatic groundwater with high levels of nitrate concentrations (10-15, 15-20, 20-30, and >30 mg x L(-1)) increased by 13.06%, 14.37%, 12.23%, and 3.85% from 2002 to 2007, while the area with low levels (0-5 and 5-10 mg x L(-1)) nitrate concentrations were decreased by 28.87% and 14.63% compared with 2002. However, the areas of confined water with nitrate concentrations of 5-10 mg x L(-1), 10-15 mg x L(-1) and 15-20 mg x L(-1) were increased by 28.01%, 9.33%, and 0.48% respectively, while the areas of NO3- -N concentration (0-5 mg x L(-1)) was decreased by 37.82%. The NO3- -N concentration in confined water was significantly negative related to groundwater depth for the two period, we found an increasing trend of NO3- -N concentration in the deeper confined water from 2002 to 2007.

[Estimating photosynthesized carbon distribution and inputs into belowground in a maize soil following 13C pulse-labeling].

Evaluating the contribution of maize growth to soil organic carbon is important for the understanding of the relationship of farmland carbon balance and agriculture production. 4 times of 13C pulse-labelling were used to estimate the photosynthesized carbon distribution at different development stages (seedling, elongation, heading and grain-filling) in maize-soil system, and quantify the carbon inputs into each part of belowground in whole growth season. The result indicated that the 13C retained aboveground reached its maximum: 80.01% among net assimilated 13C at grain-filling stage labelling. For the 4 labelling stages, the 13C transferred into belowground is 43.24%, 46.46%, 30.30% and 19.99% respectively, and of the 13C input into belowground, 34.68%-77.56% was respired by rhizosphere, 16.63%-57.02% was remain in roots and 5.05%-8.30% was incorporated into soil organic carbon by rhizodeposition. During the whole growth season of maize, the photosynthesized carbon allocated to aboveground, roots, rhizosphere respiration and soil organic carbon was 62.39%, 17.88%, 17.07% and 2.67% of the net assimilated carbon. At elongation, heading and grain-filling stages, maize's rhizosphere respiration accounted for 67.07%, 63.31% and 28.82% of the total CO2 efflux from the soil respectively, during the same period rhizosphere priming effect led to 31.11%, 79.09% and 120.83% increase of decomposition of original soil organic carbon respectively. Based on the calculation of 18 t x hm(-2) dry matter of maize for farmland production and its C content is 42%, the total carbon transferred into belowground is 4.6 t x hm(-2), among which 2.1 t x hm(-2) was respired by rhizoshphere, 2.2 t x hm(-2) was retained in roots and 0.33 t x hm(-2) was incorporated into soil organic carbon.