Predicting the climate change impacts on water-carbon coupling cycles for a loess hilly-gully watershed
JOURNAL OF HYDROLOGY
Authors: Zhao, Fubo; Wu, Yiping; Yao, Yingying; Sun, Ke; Zhang, Xuesong; Winowiecki, Leigh; Vagen, Tor-G.; Xue, Jianchu; Qiu, Linjing; Sun, Pengcheng; Sun, Yuzhu
Abstract
Understanding the climate change impacts on water and carbon cycles is of great importance for comprehensive watershed management. Although many studies have been conducted on the future climate change impacts on either water cycle or carbon cycle, the potential impacts on water-carbon coupling cycles are still poorly understood. This study used an integrated hydro-biochemical model (SWAT-DayCent) to quantitatively investigate the climate change impacts on water-carbon coupling cycles with a case study of typical loess hilly-gully watershed-the Jinghe River Basin (JRB) on the Loess Plateau. We used climate scenarios data derived under the three Representative Concentration Pathways (RCPs2.6, 4.5 and 8.5) by five downscaled Global Circulation Models (GCMs) and set two future periods of 2020-2049 (near future, NF) and 2070-2099 (far future, FF). It was projected that the annual precipitation would generally decrease slightly during the NF period but increase by 4-11% during the FF period, while the maximum/minimum air temperatures would increase significantly. The average annual streamflow would decrease (with up to 20.1% under RCP8.5) and evapotranspiration (ET) would remain almost unchanged during the NF period; however, both of them would increase during the FF period. The net primary production (NPP) would be generally higher due to the CO2 fertilization, whereas the soil organic carbon would decrease across all scenarios due to the warmer climate. The NPP-ET was projected to be closely coupled across all scenarios, and this coupling was mainly controlled by the inter-annual variability (IAV) of precipitation. Moreover, the precipitation IAV combined with NPP-ET coupling could also jointly control the NPP variability in the JRB. These projections in water-carbon coupling cycles can be useful to make better-informed decisions for future water resources and ecosystem management of the loess hilly-gully regions.
Madin-Darby canine kidney cell sialic acid receptor modulation induced by culture medium conditions: Implications for the isolation of influenza A virus
INFLUENZA AND OTHER RESPIRATORY VIRUSES
Authors: Nelson, Sarah W.; Lorbach, Joshua N.; Nolting, Jacqueline M.; Stull, Jason W.; Jackwood, Daral J.; Davis, Ian C.; Bowman, Andrew S.
Abstract
Background The influenza A virus (IAV) binds to alpha-2,3- and alpha-2,6-linked sialic acid (SA) receptors expressed by Madin-Darby canine kidney (MDCK) cells. The receptor distribution may therefore be important in regulating IAV propagation. Serum-free medium (SFM) avoids variability in conventional culture medium containing fetal bovine serum (FBS), which can have variable composition and may contain endotoxins. However, little is known about the distribution of SA receptors on cells maintained in SFM. Objectives We assessed the influence of culture media on MDCK cell SA receptor distribution along with the effect of SA receptor distribution on IAV recovery. We hypothesized that SFM would increase the proportion of alpha-2,6-linked SA receptors present and alter isolate recovery. Methods Madin-Darby canine kidney cells were cultured in medium containing FBS and two SFMs. Cell surface distribution of alpha-2,6- and alpha-2,3-linked receptors was determined using flow cytometry. Recovery of swine- and avian-lineage IAVs from MDCK cells maintained in each medium was quantified as TCID50. Results Madin-Darby canine kidney cells cultured in UltraMDCK SFM expressed both SA receptors and supported the growth of both swine- and avian-lineage IAVs. Cells maintained in other medium inconsistently expressed each receptor and the avian IAV grew to lower titers in cells cultured with FBS. Conclusions Medium conditions altered the distribution of SA receptors present on MDCK cells and affected IAV recovery. Culture in UltraMDCK SFM resulted in cells expressing both receptors and IAVs grew to higher titers than in the other culture condition, indicating that this medium may be useful for culturing IAV from multiple species.