ALBERT

Description: Five new compounds, i.e. , the three new norlignans metasequirins G–I ( 1 – 3 ) and the two new phenylpropanoids 7-(3-ethoxy-5-methoxyphenyl)propane-7,8,9-triol (=1-(3-ethoxy-5-methoxyphenyl)propane-1,2,3-triol; 4 ) and 7-(3-hydroxy-5-methoxyphenyl)propane-7,8,9-triol (=1-(3-hydroxy-5-methoxy-phenyl)propane-1,2,3-triol; 5 ), were isolated from the branches and stems of Metasequoia glyptostroboides Hu et Cheng . Their structures were elucidated by physical, chemical, and spectroscopic methods, including 1D- and 2D-NMR and HR-ESI-MS. The cytotoxicites of the five compounds were tested against A549 and Colo 205 cell lines by the MTT method.

Description: Five new compounds, i.e. , the three new norlignans metasequirins G–I ( 1 – 3 ) and the two new phenylpropanoids 7-(3-ethoxy-5-methoxyphenyl)propane-7,8,9-triol (=1-(3-ethoxy-5-methoxyphenyl)propane-1,2,3-triol; 4 ) and 7-(3-hydroxy-5-methoxyphenyl)propane-7,8,9-triol (=1-(3-hydroxy-5-methoxy-phenyl)propane-1,2,3-triol; 5 ), were isolated from the branches and stems of Metasequoia glyptostroboides Hu et Cheng . Their structures were elucidated by physical, chemical, and spectroscopic methods, including 1D- and 2D-NMR and HR-ESI-MS. The cytotoxicites of the five compounds were tested against A549 and Colo 205 cell lines by the MTT method.

Description: Three nitrophenol salts of 3, 6-dihydrazino- s -tetrazine were synthesized by the reaction of dihydrazino- s -tetrazine with either trinitrophenol, trinitroresorcinol, or trinitrophloroglucinol. Their structures were characterized by elemental analysis, FT-IR, 1 H and 13 C NMR spectroscopy, and mass spectrometry. The crystal structure of the salt of 3, 6-dihydrazino- s -tetrazine and trinitrophloroglucinol was determined by single-crystal X-ray diffraction. The thermal decomposition characteristics of the title compounds were investigated using differential scanning calorimetry and thermal gravimetry-differential thermal gravimetry and the kinetic and thermodynamic parameters were calculated. Sensitivity tests revealed that the three salts were very sensitive to external stimulus.

Description: From the aerial parts of Senecio dianthus , four new eremophilenolides ( 1 – 4 , resp.) and one new eremophilenolide alkaloid ( 5 ), of the relatively uncommon eremophilenoid-type sesquiterpenoid lactones, were isolated together with three known sesquiterpenoid lactones, 10 β -hydroxyeremophil-7(11)-en-12,8 α -olide ( 6 ), 8 β ,10 β -dihydroxyeremophil-7(11)-en-12,8 α -olide ( 7 ), and 10 α -hydroxy-1-oxoeremophila-7(11),8(9)-dien-12,8-olide ( 8 ). On the basis of IR, MS, and NMR data, particularly 2D-NMR analyses, the structures of the new compounds were established as: 2 β -(angeloyloxy)-10 β -hydroxyeremophil-7(11)-en-12,8 α -olide ( 1 ), 6 β -(angeloyloxy)-10 β -hydroxyeremophil-7(11)-en-12,8 α -olide ( 2 ), 2 β -(angeloyloxy)-8 β ,10 β -dihydroxyeremophil-7(11)-en-12,8 α -olide ( 3 ), 2 β -(angeloyloxy)-8 α -hydroxyeremophila-7(11),9(10)-dien-12,8 β -olide ( 4 ), and 8 β -amino-10 β -hydroxyeremophil-7(11)-en-12,8 α -olide ( 5 ). In addition, the relative configuration of 1 was corroborated by X-ray diffraction analysis.

Description: Understanding the dynamics and underlying mechanism of carbon exchange between terrestrial ecosystems and the atmosphere is one of the key issues in global change research. In this study, we quantified the carbon fluxes in different terrestrial ecosystems in China, and analyzed their spatial variation and environmental drivers based on the long-term observation data of ChinaFLUX sites and the published data from other flux sites in China. The results indicate that gross ecosystem productivity (GEP), ecosystem respiration (ER) and net ecosystem productivity (NEP) of terrestrial ecosystems in China showed a significantly latitudinal pattern, declining linearly with the increase of latitude. However, GEP, ER and NEP did not present a clear longitudinal pattern. The carbon sink functional areas of terrestrial ecosystems in China were mainly located in the subtropical and temperate forests, coastal wetlands in eastern China, the temperate meadow steppe in the northeast China, and the alpine meadow in eastern edge of Qinghai-Tibetan Plateau. The forest ecosystems had stronger carbon sink than grassland ecosystems. The spatial patterns of GEP and ER in China were mainly determined by mean annual precipitation (MAP) and mean annual temperature (MAT), while the spatial variation in NEP was largely explained by MAT. The combined effects of MAT and MAP explained 79%, 62% and 66% of the spatial variations in GEP, ER and NEP, respectively. The GEP, ER and NEP in different ecosystems in China exhibited ‘positive coupling correlation’ in their spatial patterns. Both ER and NEP were significantly correlated with GEP, with 68% of the per-unit GEP contributed to ER and 29% to NEP. MAT and MAP affected the spatial patterns of ER and NEP mainly by their direct effects on the spatial pattern of GEP. © 2012 Blackwell Publishing Ltd

Description: Mesenchymal stem cells (MSCs) are self-renewing cells that exhibit differentiation capacity and immune regulation ability. These versatile cells have a wide range of potential applications. However, the spontaneous differentiation and aging of MSCs during long-term culturing restrict the amount of cells available for therapies and tissue engineering. Thus, maintaining the biological characteristics of MSCs during long-term culturing is crucial. Chromatic modification via epigenetic regulatory mechanisms (e.g., histone acetylation, deacetylation, and methylation) is crucial in stem cell pluripotency. We investigated the effects of largazole or trichostatin A (TSA), a novel histone deacetylase inhibitor (HDACi), against human umbilical cord (hUC)-MSCs aging. Results show that low concentrations of largazole or TSA can significantly improve hUC-MSC proliferation and delay hUC-MSCs aging. Largazole can better improve MSC proliferation than TSA. HDACis modulate histone H3 acetylation and methylation in the telomerase reverse-transcriptase, octamer-binding transcription factor 4, Nanog, C-X-C chemokine receptor 4, alkaline phosphatase, and osteopontin genes. HDACis can promote hUC-MSC proliferation and suppress hUC-MSC spontaneous osteogenic differentiation. HDACis can affect histone H3 lysine 9 or 14 acetylation and histone H3 lysine 4 dimethylation, thus increasing the mRNA expression of pluripotent and proliferative genes and suppressing the spontaneous differentiation of hUC-MSCs. J. Cell. Biochem. © 2013 Wiley Periodicals, Inc.

Description: The mononuclear complex [Ni(HOphen)(OSO 3 )(H 2 O) 3 ] · 5H 2 O (HOphen = 1, 10-phenanthrolin-2-ol) was prepared and its single structure was determined by X-ray crystallography. In this complex, the Ni II ion has a distorted octahedral arrangement. Crystal structure analysis shows that two kinds of π–π stacking interactions and C–H ··· O short contact intermolecular interactions exist among the adjacent complexes. Fitting to the variable-temperature magnetic susceptibility data gave the magnetic coupling constant, 2 J = –0.98 cm –1 . Theoretical calculations, based on density functional theory (DFT) coupling with the broken-symmetry approach (BS), revealed that the π–π stacking magnetic coupling pathways resulted in weak ferromagnetic interactions with 2 J = 4.86 cm –1 and 2 J = 4.16 cm –1 , respectively, for the adjacent Ni II ions with separations of 8.568(19) Å and 8.749(32) Å, respectively; whereas the magnetic coupling pathway of the C–H ··· O short contact intermolecular interaction led to a weak antiferromagnetic interaction with 2 J = –17.62 cm –1 for the adjacent Ni II ions with a separation of 10.291(26) Å. The ferromagnetic coupling sign can be explained by the McConnell I spin-polarization mechanism.

Description: Both mean group size (MGS) and mean group density (MGD) are critical indices to characterize a population of cooperatively breeding birds. When a population reaches its carrying capacity, both long-term MGS and long-term MGD will remain relatively stable. However, there has been little study of how these two variables relate. The Masked laughingthrush Garrulax perspicillatus is a cooperatively breeding bird living in fragmented habitats. During 2010 and 2012-2016, we used song playback to observe and confirm the group sizes and territory ranges of the birds and the data of bird presence to determine habitat suitability. By grouping the nearest territories according to their geographical coordinates, we divided the whole study area into 12 subareas and the whole population into 12 subpopulations. Then, we calculated both MGS and MGD for different time durations for each subpopulation. Finally, using MGD as independent variable and MGS as the dependent variable, we explored the correlations between MGS and MGD by fitting quadratic functions and modeling quadratic regression. Both MGS and MGD were averaged for different time durations and were cross-related. Our results show that the MGS for more than 2 years significantly correlated with MGD for more than 3 years in a reverse parabolic shape, differing from that of short-term effects. Our findings suggest that long-term MGD is a better predictor of long-term habitat quality and that long-term MGS is determined by long-term habitat quality in Masked Laughingthrushes. Based on above findings, we can infer that: (1) Long-term habitat quality determines the long-term MGS, but it sets no prerequisite for the status and source of group members; (2) Long-term MGS in certain populations is adapted to the corresponding level of long-term habitat quality, it facilitates us to predict the helper effects on current or future survival or reproduction in different situations. These findings and inferences are both helpful for us to understand the evolution of cooperative breeding. Mean group size in cooperatively breeding system was once reported to be related to habitat quality or ecological harshness, but as positive or negative in different studies. Using the long-term mean group density (MGD) as a predictor of habitat quality, we found that the long-term mean group size is correlated to long-term MGD in a reversely quadratic way. It suggests that the social group of cooperative breeding as a whole is determined by long-term habitat quality, regardless of individual selection.

Description: Nitrogen sources and dynamics, one of the key issues in marine biogeochemical cycles, remain poorly constrained in marginal seas. Here, we examine the nitrogen cycle in the northern South China Sea (SCS) by combining data from previous reports with a new dataset of N isotopic compositions (δ 15 N) of nitrate, zooplankton and sinking particles. Average δ 15 N in subsurface nitrate is 4.8±0.3‰, similar to that of sinking particles (δ 15 N sink of 4.4‰) through the euphotic zone (EZ) collected by floating traps and to documented mean (4.6‰) for long-term mooring traps at 200 m. This along with oft-observed shallow nitracline (〈 100 m) suggests that subsurface nitrate is the primary source of new N to support export production. Moreover, δ 15 N sink at the bottom of the EZ resembles those of suspended particles (4.2±1.0‰) and zooplankton (5.4±1.0‰) inside the EZ. High similarity in δ 15 N among various types of particles including zooplankton in different size fractions in the EZ implies rapid N turnover in the ecosystem. In deep waters at 2000–3000 m, however, additional particulate N fluxes are found due to lateral transport, which contain 15 N-depleted particles, resulting in a downward decreasing trend of δ 15 N sink . Incorporation of lighter N by bacteria and selective export of picoplankton are proposed as alternative mechanisms contributing to low δ 15 N sink in the deep waters. The significant δ 15 N sink change in the deep water column makes the SCS different from most other marginal seas; thus, caution should be made when using sedimentary δ 15 N to reconstruct paleo- nitrogen processes.