ALBERT

Description: Question The ephemeral layer is an important component of the plant community in cold deserts. Conventional wisdom has it that the ephemeral layer primarily depends on early spring snowmelt water for germination and development. However, this hypothesis has never been subjected to rigorous testing. Location Southern edge of the Gurbantunggut Desert, a cold desert and a natural habitat of ephemeral plants (the inter-sand dune lowland), in the far northwest of China and around the geographical centre of the Eurasian continent. Methods At the end of the snow cover season between 2009 and 2011, four different snow treatments (0, 50, 100 and 200% snow cover, with 100% representing the natural amount of snow) were applied, using five replicates. Seedling establishment, species diversity and plant growth, population, cover and productivity were monitored throughout or sampled at the end of the growing season. Results The ephemeral plant germination and seedling density were significantly influenced by changes in snow cover. Germination, density of mature ephemeral plants and plant coverage rose as snow cover depth increased. However, the height, rooting depth, numbers of lateral roots and above-ground biomass of individual plants decreased as snow cover increased, and plant size was negatively correlated with plant density. At the ephemeral layer level, above-ground biomass showed no significant variation between snow treatments. There was also no significant difference in species richness among the snow treatments. Conclusions Increased snow resulted in higher plant density of ephemerals. However, this high density induced strong competition, reducing the body size of individual plants. By the end of the growing season, snow treatments did not induce significant changes in primary productivity of the ephemeral layer. Primary productivity or growth after seedling establishment depended mainly on rainfall that occurred after the snow had melted, not on snowmelt water itself. Thus conventional wisdom was shown to be only partially true. Snow was important to these ephemeral plants, but its role was limited to seedling establishment. Conventional wisdom has it that ephemeral plants in Gurbantonggut Desert mainly depend on snow-melted water to grow. Our results show that snow water is important for ephemeral plants, but not that important. Its role is limited to seedling establishment. Plant growth after then mainly depends on the rainfall of the growing season, not on snow-melted water.

Description: Two new cucurbitane triterpenoids, kuguacin X ( 1 ) and kuguaglycoside I ( 2 ), together with three known analogs, were isolated from immature fruits of Momordica charantia. By detailed analysis of IR, NMR, and MS data, acid hydrolysis, and comparison with spectroscopic data of known compounds, the new compounds were determined to be (23 E )-5 β ,19-epoxycucurbita-6,23-diene-3 β ,22 ξ ,25-triol ( 1 ) and (23 E )-5 β ,19-epoxycucurbita-6,23-dien-19-on-3 β ,25-diol 3- O - β - D -allopyranoside ( 2 ).

Description: ABSTRACT BACKGROUND This study aimed to investigate the effect of microRNA-30b (miR-30b) in rat myocardial ischemic-reperfusion (I/R) injury model. METHODS We randomly divided Sprague-Dawley (SD) rats (n = 80) into five groups: 1) control group; 2) miR-30b group; 3) sham-operated group; 4) I/R group and 5) I/R + miR-30b group. Real-time quantative polymerase chain reaction, immunohistochemical staining and Western blot analysis were conducted. TUNEL assay was employed for testing cardiomyocyte apoptosis. RESULTS Our results showed that miR-30b levels were down-regulated in I/R group and I/R + miR-30b group compared with sham-operated group (both P  〈 0.05). However, miR-30b level in I/R + miR-30b group was higher than I/R group ( P  〈 0.05). Markedly, the apoptotic rate in I/R group showed highest in I/R group ( P  〈 0.05). Additionally, the results illustrated that protein levels of Bcl-2, Bax and caspase-3 were at higher levels in ischemic regions in I/R group, comparing to sham-operated group (all P  〈 0.05), while Bcl-2/Bax was reduced ( P  〈 0.05). Bcl-2 level and Bcl-2/Bax were obviously increased in I/R + miR-30b group by comparison with I/R group, and expression levels of Bax and caspase-3 were down-regulated (all P  〈 0.05). We also found that in I/R + miR-30b group, KRAS level was apparently lower and p-AKT level was higher by comparing with I/R group (both P  〈 0.05). CONCLUSION Our study indicated that miR-30b overexpression had anti-apoptotic effect on early phase of rat myocardial ischemia injury model through targeting KRAS and activating the Ras/Akt pathway. This article is protected by copyright. All rights reserved

Description: Increased vascular resistance in the fetoplacental circulation is a characteristic of preeclampsia. However, the potential molecular mechanisms of this condition remain obscure. The current study aimed to determine the direct effect of the peptide antigen corresponding to the second extracellular loop of the angiotensin II type 1 receptor (AT1R-EC II ) activating autoantibody (AT1-AA), a novel risk factor in preeclamptic patients, on fetoplacental villus stem blood vessels. Immunohistochemistry revealed that AT1 receptors were localized in the veins and arteries of human placental villi. Among 58 serum samples from preeclamptic patients, 28 (48.28%) were proved AT1-AA-positive by enzyme linked immunosorbent assay [ P  〈 0.01 vs . 2/51 (3.92%) in the normal pregnancy group]. Total IgGs purified from AT1-AA-positive patients' sera (AT1-AA-IgGs) were added to isolated normal human placental blood vessels. The IgG significantly constricted both the villus veins and arteries in a dose-dependent manner in vitro , which could be blocked by the peptide corresponding to the human AT1R-EC II , anti-human IgG or the AT1 receptor antagonist losartan. Additionally, the venous constriction induced by AT1-AA-IgGs remained unchanged even at the end of the experiment (about half an hour), but the vasoconstriction caused by the AT1 receptor agonist angiotensin II underwent desensitization within three minutes. Collectively, our results demonstrated that AT1-AA in preeclamptic sera can directly constrict fetoplacental villus blood vessels without desensitization via the AT1 receptor in vitro , which might contribute to poor fetoplacental perfusion in preeclampsia. J. Cell. Physiol. © 2012 Wiley Periodicals, Inc.

Description: Boron carbide thin films have been synthesized via pulsed laser deposition process using Spark Plasma Sintered (SPSed) and dual-targets, respectively. Two kinds of structural evolutions have been found by investigation of bonding environments in as-deposited thin films via X-ray photoelectron spectroscopy study. With decreasing of B/C ratio, films deposited from SPSed-target show the transformation of B 11 C -CBB → B 11 C -CBC. In contrast, the films deposited from dual-target present the B 11 C -CBB → B 10 C 2 -CBB structural change.

Description: ABSTRACT p,p′ -dichlorodiphenyldichloroethylene ( p,p′ -DDE), the major isomer of persistent 1,1-Bis(4-chlorophenyl)−2,2,2-trichloroethane metabolite, is highly associated with the risk of liver cancer. γ-glutamyl-cysteine synthetase (γ-GCS), which is the rate-limiting enzyme of glutathione (GSH) biosynthesis and an important scavenger of reactive oxygen species (ROS), is considered as a potential therapeutic target for many cancers. However, the association between the body burden of p,p′ -DDE and γ-GCS has not been fully established. Here, we indicated that low doses of p,p′ -DDE exposure promoted the proliferation and decreased γ-GCS activity of HepG2 cells in a dose- and time-dependent manner. In addition, p,p′ -DDE elevated ROS content and attenuated glutathione peroxidase activity. This was accompanied with inhibitions of NF-E2-related factor 2 (Nrf2) at the mRNA and protein levels. ROS inhibitor supplement could significantly reverse these effects. Moreover, the addition of the proteasome inhibitor, MG132, strongly reversed the p,p′ -DDE-reduced Nrf2 expression and γ-GCS activity. Consistently, GSH content was in line with the alteration of γ-GCS. Collectively, the results indicate that p,p′ -DDE treatment downregulates γ-GCS activity in HepG2 cells by inducing ROS-mediated Nrf2 loss. © 2014 Wiley Periodicals, Inc. Environ Toxicol, 2014.

Description: Limited data are available on the physiological responses of leaves from fruiting trees to magnesium (Mg) deficiency. Magnesium deficiency–induced effects on photosystem II (PSII) photochemistry in leaves of fruiting ( Citrus reticulate cv. Ponkan) trees were assessed by the chlorophyll a fluorescence (OJIP) transient. Magnesium deficiency decreased leaf CO 2 assimilation and carbohydrates, but had no effect on intercellular CO 2 concentration. Activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and concentrations of Chlorophyll (Chl) and carotenoids (Car) decreased to a lesser extent than CO 2 assimilation. Chlorophyll a fluorescence transient from Mg-deficient leaves had increased O step and decreased P step, accompanied by positive ΔL, ΔK, ΔJ, and ΔI bands. Magnesium deficiency decreased maximum quantum yield of primary photochemistry ( F v / F m ), quantum yield of electron transport from Q〈$〉_A^-〈$〉 to the photosystem I (PSI) end electron acceptors (φ R0 ), maximum amplitude of IP phase and total performance index (PI tot, abs ), but increased deactiviation of oxygen-evolving complex (OEC) and energy dissipation. Magnesium-deficient leaves had higher or similar activities of antioxidant enzymes except for lower catalase (CAT) activity, higher or similar concentrations of antioxidant metabolites, and a higher ratio of Car : Chl. Magnesium-deficiency did not affect concentration of malondialdehyde (MDA) and ratios of ascorbate (ASC) to ASC + dehydroascorbate (DHA) and reduced glutathione (GSH) to GSH + oxidized glutathione (GSSG). In conclusion, Mg deficiency–induced impairment of the whole photosynthetic electron transport chain may be the main factor contributing to decreased CO 2 assimilation. Enhanced energy dissipation and antioxidant metabolism provide sufficient protection to Mg-deficient leaves against photo-oxidative damage.

Description: Abstract In January of 2016, the Ross Sea sector of the West Antarctica Ice Sheet experienced a three‐week long melting episode. Here we quantify the association of the large‐extent and long‐lasting melting event with the enhancement of the downward longwave (LW) radiative fluxes at surface due to water vapor, cloud, and atmospheric dynamic feedbacks using the ERA‐Interim dataset. The abnormally long‐lasting temporal surges of atmospheric moisture, warm air, and low‐level clouds increase the downward LW radiative energy flux at the surface during the massive ice‐melting period. The concurrent timing and spatial overlap between poleward wind anomalies and positive downward LW radiative surface energy flux anomalies over West Antarctica due to warmer air temperature and increases in atmospheric water vapor and cloud coverage provide direct evidence that warm and moist air advection from lower latitudes to West Antarctica causes the rapid long‐lasting warming and vast ice mass loss in January of 2016.

Description: Abstract Previously, we found 3C‐SiC films favor to grow in 〈111〉 orientation on Si (110) (https://doi.org/10.1111/jace.15260). However, epitaxial growth of thick 〈110〉‐3C‐SiC is still a big challenge. In this study, thick 3C‐SiC (110) epitaxial films were prepared on Si (110) substrate by laser chemical vapor deposition (LCVD) using hexamethyldisilane (HMDS) in H2 atmosphere. The investigation of growth mechanism showed that the laser of LCVD played an important role during the depositions. Observation by high‐resolution transmission electron microscopy (HRTEM) revealed that the interface of 3C‐SiC (110)/Si (110) exhibited rough texture at atomic level. The atomic roughness on Si (110) surface could be a key factor for 3C‐SiC (110) nucleation. The growth of thick 3C‐SiC (110) epitaxial films could be very promising for new development in power electronics applications.