Search

Abstract: To assess the impacts of yak excreta patches on greenhouse gas (GHG) fluxes in the alpine meadow of the Qinghai-Tibetan plateau, methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O) fluxes were measured for the first time from experimental excreta patches placed on the meadow during the summer grazing seasons in 2005 and 2006. Dung patches were CH4 sources (average 586μgm−2 h−1 in 2005 and 199μgm−2 h−1 in 2006) during the investigation period of two years, while urine patches (average −31μgm−2 h−1 in 2005 and −33μgm−2 h−1 in 2006) and control plots (average −28μgm−2 h−1 in 2005 and −30μgm−2 h−1 in 2006) consumed CH4. The cumulative CO2 emission for dung patches was about 36–50% higher than control plots during the experimental period in 2005 and 2006. The cumulative N2O emissions for both urine and dung patches were 2.1–3.7 and 1.8–3.5 times greater than control plots in 2005 and 2006, respectively. Soil water-filled pore space (WFPS) explained 35% and 36% of CH4 flux variation for urine patches and control plots, respectively. Soil temperature explained 40–75% of temporal variation of CO2 emissions for all treatments. Temporal N2O flux variation in urine patches (34%), dung patches (48%), and control (56%) plots was mainly driven by the simultaneous effect of soil temperature and WFPS. Although yak excreta patches significantly affected GHG fluxes, their contributions to the whole grazing alpine meadow in terms of CO2 equivalents are limited under the moderate grazing intensity (1.45yakha−1). However, the contributions of excreta patches to N2O emissions are not negligible when estimating N2O emissions in the grazing meadow. In this study, the N2O emission factor of yak excreta patches varied with year (about 0.9–1.0%, and 0.1–0.2% in 2005 and 2006, respectively), which was lower than IPCC default value of 2%. [Copyright &y& Elsevier]

There is a need for methodology to warm open-field plots in order to study the likely effects of global warming on ecosystems in the future. Herein, we describe the development of arrays of more powerful and efficient infrared heaters with ceramic heating elements. By tilting the heaters at 45° from horizontal and combining six of them in a hexagonal array, good uniformity of warming was achieved across 3-m-diameter plots. Moreover, there do not appear to be obstacles (other than financial) to scaling to larger plots. The efficiency [ ηh (%); thermal radiation out per electrical energy in] of these heaters was higher than that of the heaters used in most previous infrared heater experiments and can be described by: ηh= 10 + 25exp(− 0.17 u), where u is wind speed at 2 m height (m s− 1). Graphs are presented to estimate operating costs from degrees of warming, two types of plant canopy, and site windiness. Four such arrays were deployed over plots of grass at Haibei, Qinghai, China and another at Cheyenne, Wyoming, USA, along with corresponding reference plots with dummy heaters. Proportional integral derivative systems with infrared thermometers to sense canopy temperatures of the heated and reference plots were used to control the heater outputs. Over month-long periods at both sites, about 75% of canopy temperature observations were within 0.5 °C of the set-point temperature differences between heated and reference plots. Electrical power consumption per 3-m-diameter plot averaged 58 and 80 kW h day− 1 for Haibei and Cheyenne, respectively. However, the desired temperature differences were set lower at Haibei (1.2 °C daytime, 1.7 °C night) than Cheyenne (1.5 °C daytime, 3.0 °C night), and Cheyenne is a windier site. Thus, we conclude that these hexagonal arrays of ceramic infrared heaters can be a successful temperature free-air-controlled enhancement (T-FACE) system for warming ecosystem field plots. [ABSTRACT FROM AUTHOR]

Abstract: A great deal of uncertainty is associated with estimates of global nitrous oxide (N2O) emissions because emissions from arid and polar climates were not included in the estimates due to a lack of available data. In particular, very few studies have assessed the response of N2O flux to grazing under future warming conditions. This experiment was conducted to determine the effects of warming and grazing on N2O flux at different time scales for three years under a controlled warming-grazing system. A free-air temperature enhancement system (FATE) using infrared heaters and grazing significantly increased soil temperatures for both of growing (average 1.8 °C in 2008) and no-growing seasons (average 3.0 °C for 3-years) within 20-cm depth, but only warming reduced soil moisture at 10-cm soil depth during the growing season during the drought year of 2008. Generally, the effects of warming and grazing on N2O flux varied with sampling date, season, and year. No interactive effect between warming and grazing was found. Warming did not affect annual N2O flux when grazing was moderate during the growing season because the tradeoff of the effect of warming on N2O flux was observed between the growing season and no-growing season. No-warming with grazing (NWG) and warming with grazing (WG) significantly increased the average annual N2O flux (57.8 and 31.0%) compared with no-warming with no-grazing (NWNG) and warming with no-grazing (WNG), respectively, indicating that warming reduced the response of N2O flux to grazing in the region. Winter accounted for 36–57% of annual N2O flux for NWNG and NWG, whereas only for 5–8% of annual N2O flux for WNG and WG. Soil temperature could explain 5–35% of annual N2O flux variation. [Copyright &y& Elsevier]

A Gram-negative and rod-shaped bacterium, designated C340-1 T , was isolated and screened from paddy soil in Zhongshan County, Guangxi Province, PR China. This strain grew at 20-42 °C (optimum, 37 °C), pH 5.0-9.0 (optimum, pH 7.0) and 0-4 % (w/v) NaCl (optimum, 0-1 %) on Reasoner's 2A medium. The strain could fix atmospheric nitrogen and acetylene reduction activity was recorded up to 120.26 nmol ethylene h -1 (mg protein) -1 . Q-10 was the only isoprenoid quinone component; phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, an unidentified aminolipid and an unidentified polar lipid were the major polar lipids. Summed feature 8 (C 18 : 1  ω 7 c and/or C 18 : 1  ω 6 c ) and summed feature 3 (C 16 : 1  ω 7 c and/or C 16 : 1  ω 6 c ) were the primary cellular fatty acids. The genome of strain C340-1 T was 6.18 Mb, and the G+C content was 69.0 mol%. Phylogenetic tree analysis based on 16S rRNA gene and 92 core genes showed that strain C340-1 T was closely related to and clustered with the type strains Azospirillum brasilense JCM 1224 T , Azospirillum argentinense Az39 T , Azospirillum baldaniorum Sp245 T and Azospirillum formosense JCM 17639 T . The average nucleotide identity (ANI), average amino acid identity (AAI) and digital DNA-DNA hybridization (dDDH) values between strain C340-1 T and the closely related type strains mentioned above were significantly lower than the threshold values for species classification (95-96 %, 95-96 % and 70 %, respectively). Based on phylogenetic, genomic, phenotypic, physiological and biochemical data, we have reason to believe that C340-1 T represents a new species of the genus Azospirillum , for which the name Azospirillum isscasi sp. nov. is proposed. The type strain is C340-1 T (=CCTCC AB 2023105 T =KCTC 8126 T ).

Objective: Sevoflurane is used in anesthesia for surgery including in organ transplantation. We investigated the role of a non-coding single-stranded microRNA, miR-495-3p, in the sevoflurane-induced neurotoxicity using a mouse hippocampal neuronal cell line (HT22)., Methods: The levels of miR-495-3p in sevoflurane-exposed mice and HT22 cells were determined via RT-qPCR. The role of miR-495-3p on cell viability and apoptosis were determined by CCK-8 and flow cytometric assay, respectively. Western blotting was explored to measure levels of Bax, Bcl-2, active caspase 3, BDNF, p-ERK/ERK and p-CREB/CREB in HT22 cells. ELISA assay was used to examine the levels of reactive oxygen species (ROS), superoxide dismutase (SOD) and glutathione peroxidase (GPX) in cells. Dual luciferase reporter assay was used to explore the interaction of miR-495-3p and BDNF., Results: The level of miR-495-3p was increased sevoflurane-exposed mice and in sevoflurane-treated HT22 cells. Downregulation of miR-495-3p inhibited sevoflurane-induced apoptosis and promoted cell proliferation by upregulating the proteins of Bcl-2 and downregulating the expressions of Bax and active caspase-3 in HT22 cells. In addition, inhibition of miR-495-3p alleviated sevoflurane-induced oxidative injuries in HT22 cells via decline of ROS and upregulation of SOD and GPX. MiR-495-3p can inhibit the ERK/CREB pathway by targeting BDNF., Conclusion: Downregulation of miR-495-3p can decrease oxidative status in HT22 cells and alleviate sevoflurane-induced cytotoxicity through stimulating the BDNF/ERK/CREB pathway., Competing Interests: Declaration of Competing Interest There are no any competing interests., (Copyright © 2022 Elsevier B.V. All rights reserved.)