Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    The effect of microbial inoculant origin on the rhizosphere bacterial community composition and plant growth-promotion
    Gu, Yian ; Dong, Ke ; Geisen, Stefan ; Yang, Wei ; Yan, Yaner ; Gu, Dalu ; Liu, Naisen ; Borisjuk, Nikolai ; Luo, Yuming ; Friman, Ville Petri - \ 2020
    Plant and Soil 452 (2020). - ISSN 0032-079X - p. 105 - 117.
    Diversity - Microbial inoculation - Microbial transplants - Plant growth-promotion - Rhizosphere microbiota - Soil functioning

    Aims: Microbial inoculation has been proposed as a potential approach for rhizosphere engineering. However, it is still unclear to what extent successful plant growth-promoting effects are driven by the origin of the microbial inocula and which taxa are responsible for the plant-beneficial effects. Methods: We conducted a microbial transplant experiment by using different microbial inocula (and nutrient controls) isolated from forest, soybean and tomato field soils and determined their effects on tomato plant biomass and nutrient assimilation in sterilized tomato soil. Rhizosphere bacterial communities were compared at the end of the experiment and correlative and machine learning analyses used to identify potential keystone taxa associated with the plant growth-promotion. Results: Microbial inoculants had a clear positive effect on plant growth compared to control nutrient inoculants. Specifically, positive effects on the plant biomass were significantly associated with microbial inoculants from the forest and soybean field soils, while microbial inoculants from the forest and tomato field soils had clear positive effects on the plant nutrient assimilation. Soil nutrients alone had relatively minor effects on rhizosphere bacterial communities. However, the origin of microbial inoculants had clear effects on the structure of bacterial community structure with tomato and soybean inoculants having positive effects on the diversity and abundance of bacterial communities, respectively. Specifically, Streptomyces, Luteimonas and Enterobacter were identified as the potential keystone genera affecting plant growth. Conclusions: The origin of soil microbiome inoculant can predictably influence plant growth and nutrient assimilation and that these effects are associated with certain key bacterial genera.

    Direct and quantitative in-situ analysis of third-hand smoke in and on various matrices by ambient desorption corona beam ionization mass spectrometry
    Min, Ke ; Guo, Ping ; Chen, Dongying ; Huang, Si ; Luo, Wei ; Ma, Ming ; Chen, Bo ; Yao, Shouzhou ; Zuilhof, H. - \ 2020
    Talanta 219 (2020). - ISSN 0039-9140
    Third-hand smoke (THS) is composed of surface-deposited remnants resulting from tabacco-smoking. Because THS components have properties of remaining on, re-emitting from and reacting on and with surfaces, in-situ analysis of the components on different surfaces is both in high demand and challenging. The aim of this study is to establish desorption corona beam ionization (DCBI)-MS/MS as an analytical tool for THS research. To this end, an in-situ DCBI-MS/MS approach was developed for the quantitative analysis of typical THS environmental markers, i.e. nicotine and cotinine on different surfaces such as fruits, cotton clothing, glass, and toys etc. The limits of detection of nicotine and cotinine were both 1.4 μg m-2. Low-temperature DCBI-MS/MS was applied to the direct detection of THS on fingers without any skin damage. Smoking-related biomarkers analyses in urine were accomplished, with a 10 s DCBI analysis time. The on-surface tobacco-specific nitrosamines (TSNAs), such as 1-(N-methyl-N-nitrosamino)-1-(3-pyridinyl)-4-butanal) (NNA), 4-(methylnitrosamino)-1-(3-pyridinyl)-1-butanone (NNK), and N-nitroso nornicotine (NNN) were in-situ successfully detected in dust samples.
    Long-term nitrogen loading alleviates phosphorus limitation in terrestrial ecosystems
    Chen, Ji ; Groenigen, Kees J. van; Hungate, Bruce A. ; Terrer, César ; Groenigen, Jan Willem van; Maestre, Fernando T. ; Ying, Samantha C. ; Luo, Yiqi ; Jørgensen, Uffe ; Sinsabaugh, Robert L. ; Olesen, Jørgen E. ; Elsgaard, Lars - \ 2020
    Global Change Biology 26 (2020)9. - ISSN 1354-1013 - p. 5077 - 5086.
    microbial biomass - nitrogen addition - nutrient stoichiometry balance - phosphorus limitation - soil nitrogen content - soil pH - soil phosphatase activity - soil phosphorus content

    Increased human-derived nitrogen (N) deposition to terrestrial ecosystems has resulted in widespread phosphorus (P) limitation of net primary productivity. However, it remains unclear if and how N-induced P limitation varies over time. Soil extracellular phosphatases catalyze the hydrolysis of P from soil organic matter, an important adaptive mechanism for ecosystems to cope with N-induced P limitation. Here we show, using a meta-analysis of 140 studies and 668 observations worldwide, that N stimulation of soil phosphatase activity diminishes over time. Whereas short-term N loading (≤5 years) significantly increased soil phosphatase activity by 28%, long-term N loading had no significant effect. Nitrogen loading did not affect soil available P and total P content in either short- or long-term studies. Together, these results suggest that N-induced P limitation in ecosystems is alleviated in the long-term through the initial stimulation of soil phosphatase activity, thereby securing P supply to support plant growth. Our results suggest that increases in terrestrial carbon uptake due to ongoing anthropogenic N loading may be greater than previously thought.

    Effects of Early and Current Environmental Enrichment on Behavior and Growth in Pigs
    Luo, Lu ; Reimert, Inonge ; Middelkoop, Anouschka ; Kemp, Bas ; Bolhuis, J.E. - \ 2020
    Frontiers in Veterinary Science 7 (2020). - ISSN 2297-1769
    behavior - early life - environmental enrichment - feed intake - growth - pigs

    Enriched environments are known to beneficially affect the behavior of pigs, as compared with barren pens. The influence of enrichment may, however, depend on pigs' early life housing experiences. The aim of this study was to investigate the long-term effects of early and later life environmental enrichment on behavior and growth in pigs with different coping styles. Pigs were housed in either barren pens or in larger pens enriched with rooting substrates from birth, and half of them experienced a housing switch, i.e., a loss or gain of enrichment, at 7 weeks of age, creating four treatment groups. Home pen behavior and body weight were recorded until 19 weeks of age. Pigs were classified as reactive or proactive based on a backtest at 2 weeks of age. Enrichment increased time spent exploring, chewing, and play and decreased oral manipulation of penmates and pen-directed exploring and chewing. Behavior of pigs that switched from barren to enriched pens or vice versa reflected not only their actual environment, but also their early life housing. As early and later life enrichment affected most behaviors in opposite directions, effects of enrichment, or lack thereof, after the switch were more pronounced in pigs that had experienced a different early life condition. For instance, pigs experiencing an upgrade from barren to enriched pens seemed to “catch-up” by showing more exploration and play. Conversely, pigs exposed to a downgrade displayed more oral manipulation of penmates than ones kept barren throughout, which particularly held for pigs with a reactive coping style. Effects of early life and current housing on several other behaviors depended on coping style too. Pigs housed in enriched conditions appeared better able to cope with weaning than barren housed pigs, as they gained more weight and had higher feed intake post-weaning. Barren housed pigs had a lower body weight than enriched pigs just before the switch, after which growth was mainly determined by actual housing, with enriched kept pigs having a higher feed intake and body weight. Thus, not only current housing conditions, but also a (mis)match with the early life environment may affect behavior and growth of pigs.

    Hydrothermal processes of near-surface warm permafrost in response to strong precipitation events in the Headwater Area of the Yellow River, Tibetan Plateau
    Luo, Dongliang ; Jin, Huijun ; Bense, Victor F. ; Jin, Xiaoying ; Li, Xiaoying - \ 2020
    Geoderma 376 (2020). - ISSN 0016-7061
    Aquifer - Aquitard - Headwater Area of the Yellow River - Seasonal freeze-thaw processes - Tibetan Plateau - Warm permafrost

    Permafrost is mostly warm and thermally unstable on the Tibetan Plateau (TP), particularly in some marginal areas, thereby being susceptible to degrade or even disappear under climate warming. The degradation of permafrost consequently leads to changes in hydrological cycles associated with seasonal freeze-thaw processes. In this study, we investigated seasonal hydrothermal processes of near-surface permafrost layers and their responses to rain events at two warm permafrost sites in the Headwater Area of the Yellow River, northeastern TP. Results demonstrated that water content in shallow active layers changed with infiltration of rainwater, whereas kept stable in the perennially frozen layer, which serves as an aquitard due to low hydraulic conductivity or even imperviousness. Accordingly, the supra-permafrost water acts as a seasonal aquifer in the thawing period and as a seasonal aquitard in the freezing period. Seasonal freeze-thaw processes in association with rain events correlate well with the recharge and discharge of the supra-permafrost water. Super-heavy precipitation (44 mm occurred on 2 July 2015) caused a sharp increase in soil water content and dramatic rises in soil temperatures by 0.3–0.5 °C at shallow depths and advancement thawing of the active layer by half a month. However, more summer precipitation amount tends to reduce the seasonal amplitude of soil temperatures, decrease mean annual soil temperatures and thawing indices and thin active layers. High salinity results in the long remaining of a large amount of unfrozen water around the bottom of the active layer. We conclude that extremely warm permafrost with TZAA (the temperature at the depth of zero annual amplitude) >−0.5 °C is likely percolated under heavy and super-heavy precipitation events, while hydrothermal processes around the permafrost table likely present three stages concerning TZAA of <−0.5 °C, −0.5–0 °C, and >0 °C.

    Better pens mean better pigs
    Luo, Lu - \ 2020
    Regulation of endoplasmic reticulum-mitochondria contacts and mitochondrial dynamics by Sel1L-Hrd1 ERAD during thermogenesis
    Zhou, Zhangsen ; Torres, Mauricio ; Sha, Haibo ; Halbrook, Christopher J. ; Bergh, Françoise van den; Reinert, Rachel B. ; Yamada, Tatsuya ; Wang, Siwen ; Luo, Yingying ; Hunter, Allen H. ; Wang, Chunqing ; Sanderson, Thomas H. ; Liu, Meilian ; Taylor, Aaron ; Sesaki, Hiromi ; Lyssiotis, Costas A. ; Wu, Jun ; Kersten, Sander ; Beard, Daniel A. ; Qi, Ling - \ 2020
    Wageningen University
    GSE145895 - PRJNA608688 - Mus musculus
    Organelles such as endoplasmic reticulum (ER) and mitochondria interact with each other at specialized domains on the ER known as mitochondria-associated membranes (MAMs). Here, using three-dimensional high-resolution imaging techniques, we show that the Sel1LHrd1 protein complex, the most conserved branch of ER-associated protein degradation (ERAD), exerts a profound impact on ER-mitochondria contacts and mitochondrial dynamics, at least in part, by regulating the turnover and hence the abundance of the MAM protein sigma receptor 1 (SigmaR1). Sel1L or Hrd1 deficiency in brown adipocytes impairs dynamic interaction between ER and mitochondria, leading to the formation of pleomorphic “megamitochondria” and, in some cases with penetrating ER tubule(s), in response to acute cold challenge. Mice with ERAD deficiency are cold sensitive and exhibit mitochondrial dysfunction in brown adipocytes. Mechanistically, endogenous SigmaR1 is targeted for proteasomal degradation by Sel1L-Hrd1 ERAD, whose accumulation in ERAD-deficient cells leads to mitofusin 2 (Mfn2) oligomerization, thereby linking ERAD to mitochondrial dynamics. Our study identifies Sel1L-Hrd1 ERAD as a critical determinant of ER-mitochondria contacts, thereby regulating mitochondrial dynamics and thermogenesis.
    Endoplasmic reticulum-associated degradation regulates mitochondrial dynamics in brown adipocytes
    Zhou, Zhangsen ; Torres, Mauricio ; Sha, Haibo ; Halbrook, Christopher J. ; Bergh, Françoise van den; Reinert, Rachel B. ; Yamada, Tatsuya ; Wang, Siwen ; Luo, Yingying ; Hunter, Allen H. ; Wang, Chunqing ; Sanderson, Thomas H. ; Liu, Meilian ; Taylor, Aaron ; Sesaki, Hiromi ; Lyssiotis, Costas A. ; Wu, Jun ; Kersten, Sander ; Beard, Daniel A. ; Qi, Ling - \ 2020
    Science 368 (2020)6486. - ISSN 0036-8075 - p. 54 - 60.

    The endoplasmic reticulum (ER) engages mitochondria at specialized ER domains known as mitochondria-associated membranes (MAMs). Here, we used three-dimensional high-resolution imaging to investigate the formation of pleomorphic “megamitochondria” with altered MAMs in brown adipocytes lacking the Sel1L-Hrd1 protein complex of ER-associated protein degradation (ERAD). Mice with ERAD deficiency in brown adipocytes were cold sensitive and exhibited mitochondrial dysfunction. ERAD deficiency affected ER-mitochondria contacts and mitochondrial dynamics, at least in part, by regulating the turnover of the MAM protein, sigma receptor 1 (SigmaR1). Thus, our study provides molecular insights into ER-mitochondrial cross-talk and expands our understanding of the physiological importance of Sel1L-Hrd1 ERAD.

    Effects of early life and current environmental enrichment on behaviour, affective state and immunity in pigs
    Luo, Lu - \ 2020
    Wageningen University. Promotor(en): B. Kemp, co-promotor(en): J.E. Bolhuis; H.K. Parmentier. - Wageningen : Wageningen University - ISBN 9789463953290 - 356

    The main aim of this thesis was to investigate whether and how early life and current environmental enrichment affect behaviour, affective state, and immunity (which may influence health) in pigs.

    First of all, the effects of environmental enrichment on natural (auto)antibodies (NA(A)b) in relative healthy pigs and in pigs co-infected with PRRSV and A. pleuropneumoniae were studied.  We found that environmental enrichment per se has an impact on immunity in pigs, by affecting NA(A)b levels and their changes in response to challenges and infection.

    Thereafter we aimed to further investigate the effects of early life environmental enrichment and a (mis)match in early life and current housing on behaviour, affective state, and immunity in pigs. To this aim, 30 litters of pigs were housed in either barren or enriched pens from birth. The coping style of the pigs was assessed by the backtest, and pigs were classified as reactive (LR) or proactive (HR). At 28 days of age, pigs were weaned, and in total 192 pigs were selected and regrouped in 32 new pens containing 6 non-littermate pigs each. All pigs were equally regrouped by taking sex, coping style and body weight into account. Housing treatment (barren vs. enriched) for each pig was kept the same as before weaning. At 47 days of age, half of the groups of pigs experienced a switch in housing type, and the other half did not. Thus, after the switch, there were four housing treatment groups: barren-barren (B1B2), barren-enriched (B1E2), enriched-enriched (E1E2) and enriched-barren (E1B2), n=8 pens per group.

    In the home pen observations, environmental enrichment increased time spent on exploring, chewing and play, and decreased damaging behaviours directed at pen mates, such as tail biting and ear biting, and pen-directed exploring and chewing. Behaviour of pigs that switched from barren to enriched pens or vice versa reflected not only their current environment, but also their early life housing conditions. Effects of early life and current enrichment on most behaviours were in opposite direction. The effects of (lack of) enrichment after the switch were therefore more pronounced in pigs that had experienced a different early life condition.   This might reflect frustration in pigs that switched from enriched to barren pens, and a ‘catching up’ effect in pigs that went from barren to enriched pens. For some behaviours this effect of the switch was affected by the coping style of the pigs.  For instance, the LR pigs that switched from enriched to barren pens showed more damaging behaviours directed at their pen mates than all other pigs. Enriched pigs gained more weight and had a higher feed intake in the first weeks post-weaning, suggesting that they were better able to cope with the weaning transition. Barren housed pigs had a lower body weight than enriched pigs just before the switch, after which growth was mainly determined by actual housing, with enriched kept pigs having a higher feed intake and final body weight.

    Barren housed pigs were expected to have a more negative affective state than enriched pigs, and even more so if they originated from an enriched early life environment. To investigate whether housing experiences in early life, and a (mis)match with current housing conditions, would have long-term effects on affective state, pigs were exposed to an attention bias test (ABT) and successive negative contrast test (SNC). In the ABT, current housing, but not early life housing, affected behaviour in a coping-style-dependent manner, as E2-HR pigs paid attention towards the threat more frequently, were more likely to utter high-pitched vocalisations and walked more compared to (part of) the other groups. This unexpected effect could be related to the larger contrast between the pigs’ home pen and the test environment for enriched housed pigs. The behaviour in the ABT may therefore have reflected a short-term effect of the test, rather than the long-term effect of housing, on affective state.  In the SNC, B1B2 pigs generally had a lower probability and higher latency to get the reward than other pigs. HR pigs ran overall slower than LR pigs. Reward downshift increased the latency and reduced the probability to get to the reward, but only in pigs exposed to barren conditions in early life, which thus were more sensitive to reward loss than pigs from enriched early life housing.

    To assess the effects of early life and current housing conditions on innate and adaptive immune competence, 64 pigs were primary  and secondary immunized with the same dose of KLH-TNP. Blood samples were collected, and IgM and IgG antibody responses and leukocyte subpopulations were measured. We found that both early life and later life enrichment, and, notably, a switch in housing conditions influenced specific antibodies and leukocyte subpopulations in pigs. Regarding the relative frequencies of leukocyte subsets, the immune system seemed to respond to a change in housing condition, in either direction, rather than to the long-term effects of housing per se.

    Lastly, the relationships between immunity and behaviour and/or affective states were explored, indicating that play behaviour in the home pen and growth were found to relate to immunity to some extent.

    To conclude, this thesis confirms that environmental enrichment has positive effects on the behaviour of pigs. It also indicates that switching from enriched to barren conditions is more detrimental for pigs’ behaviour than housing in barren pens throughout. Effects of environmental enrichment on behaviour in tests of affective state were equivocal. Both early life and current housing, and a switch in housing conditions influenced specific antibody levels and the frequencies of leukocyte subpopulations in pigs, and the immune system seems to be alerted by changes in the environment.  The results of this thesis underline the importance of enrichment for pigs, as well as a fit between their early and later life housing conditions.

    Early and later life environmental enrichment affect specific antibody responses and blood leukocyte subpopulations in pigs
    Luo, Lu ; Jansen, Christine A. ; Bolhuis, Elizabeth ; Arts, Joop ; Kemp, Bas ; Parmentier, Henk - \ 2020
    Physiology and Behavior 217 (2020). - ISSN 0031-9384
    Antibody response - Coping style - Early life history - Enrichment - Immunity - Pigs

    This study addressed the impact of early and later life environmental enrichment, and their combination, on specific antibody responses and peripheral blood leukocyte subpopulations in pigs. Pigs were kept in either barren (B1) or enriched (E1) housing from birth, and half of the pigs switched to barren or enriched housing on day 47, resulting in four treatment combinations: B1B2, B1E2, E1B2, E1E2). Pigs were immunized with keyhole limpet hemocyanin-conjugated trinitrophenyl (KLH-TNP) on day 74 and 109 to induce primary and secondary antibody responses. Blood samples were taken weekly until day 130, and IgM and IgG antibody responses were measured. Leukocyte subpopulations were measured on day 74 and 130. Time course of the antibody responses was not affected by housing. Early life enrichment increased the IgG response to KLH, particularly the primary one. At day 74 the relative frequency of lymphocytes, DC and SLA-II expression on monocytes were higher in E1 pigs, whereas the percentage of granulocytes tended to be lower in E1 pigs at day 74. Early life enrichment increased the SLA-II expression on monocytes, the granulocyte to lymphocyte ratio, and tended to increase the percentage of granulocytes, but tended to decrease the percentage of monocytes at day 130. Later life enrichment reduced percentages of CD4+CD8α+ T cells before and after immunization and the SLA-II expression on monocytes at day 74, the percentage of granulocytes and the granulocyte to lymphocyte ratio at day 130. Notably, early and later life housing interacted in their effects on several immune parameters. KLH-IgM responses (both primary and secondary) were affected by the interaction between early and later life housing. IgM titers were higher for B1B2 than for E1E2, with the switched animals (B1E2 and E1B2) moving towards the titers of the animals kept in their later life environment from birth onwards. At day 130 the percentage of gamma delta T cells, CD8α+ cytotoxic T cells and DC were not different between pigs kept in B1B2 and E1E2, but there was a clear impact of the switch in housing conditions, particularly for the pigs that changed from barren to enriched housing. We also found effects of coping style (personality) and sex on some immune parameters. In conclusion, both early life and later life enrichment, and, notably a switch in housing conditions influenced specific antibodies and leukocyte subpopulations in pigs. The current study implies that the early life history of animals and the (mis)match with their current environment could thus be of major importance for their immune system. Further research is needed to investigate potential consequences for the pigs’ health.

    Effects of early life and current housing on sensitivity to reward loss in a successive negative contrast test in pigs
    Luo, L. ; Reimert, I. ; Graat, E.A.M. ; Smeets, S. ; Kemp, B. ; Bolhuis, J.E. - \ 2020
    Animal Cognition 23 (2020)1. - ISSN 1435-9448 - p. 121 - 130.
    Affective state - Coping style - Early life - Enrichment - Pigs - Reward loss

    Animals in a negative affective state seem to be more sensitive to reward loss, i.e. an unexpected decrease in reward size. The aim of this study was to investigate whether early-life and current enriched vs. barren housing conditions affect the sensitivity to reward loss in pigs using a successive negative contrast test. Pigs (n = 64 from 32 pens) were housed in barren or enriched conditions from birth onwards, and at 7 weeks of age experienced either a switch in housing conditions (from barren to enriched or vice versa) or not. Allotting pigs to the different treatments was balanced for coping style (proactive vs. reactive). One pig per pen was trained to run for a large reward and one for a small reward. Reward loss was introduced for pigs receiving the large reward after 11 days (reward downshift), i.e. from then onwards, they received the small reward. Pigs housed in barren conditions throughout life generally had a lower probability and higher latency to get the reward than other pigs. Proactive pigs ran overall slower than reactive pigs. After the reward downshift, all pigs ran slower. Nevertheless, reward downshift increased the latency and reduced the probability to get to the reward, but only in pigs exposed to barren conditions in early life, which thus were more sensitive to reward loss than pigs from enriched early life housing. In conclusion, barren housed pigs seemed overall less motivated for the reward, and early life housing conditions had long-term effects on the sensitivity to reward loss.

    Negative effects of urbanization on agricultural soil easily oxidizable organic carbon down the profile of the Chengdu Plain, China
    Luo, Youlin ; Li, Qiquan ; Wang, Changquan ; Li, Bing ; Stomph, Tjeerd Jan ; Yang, Juan ; Tao, Qi ; Yuan, Shu ; Tang, Xiaoyan ; Ge, Jinru ; Yu, Xuelian ; Peng, Yueyue ; Xu, Qiang ; Zheng, Gangxun - \ 2020
    Land Degradation and Development 31 (2020)3. - ISSN 1085-3278 - p. 404 - 416.
    easily oxidized organic carbon - impact factors - negative effects - rapid urbanization - soil profile

    Soil easily oxidizable organic carbon (EOC) is directly related to CO2 density; dynamics in subsurface EOC have been observed globally in relation to rapid urbanization. However, in the context of rapid urbanization, the factors related to EOC and the response of the EOC pool to urbanization down the profile remain elusive. The aim of the current paper is to investigate possible changes in the distribution of EOC over the soil profile and the impact of land use, socioeconomic, and natural factors on these. The study used samples from 182 soil profiles (0–100 cm) taken in the peri-urban areas of the megacity Chengdu (a typical megacity with rapid urbanization). Main drivers of changes in soil EOC were analyzed by using spatial and regression analyses. Closer to the centre of the city, soil EOC levels were lower and land-use factors and socioeconomic factors contributed more to explaining variation in EOC levels in the 0–40-cm layer, whereas natural factors were most important at larger distance from the city. The effect of land-use factors and socioeconomic factors on EOC reached down to 60-cm depths. Moreover, an estimated 20% loss of EOC stock was observed close to the city in comparison with the surroundings, suggesting that the rapid process of urbanization was accompanied by a loss of EOC stock down the profile to depths of 60 cm, and the negative effects on EOC stock became more intensive as the distance to the city decreased.

    The fertilization effect of global dimming on crop yields is not attributed to an improved light interception
    Shao, Liping ; Li, Gang ; Zhao, Qiannan ; Li, Yabing ; Sun, Yutong ; Wang, Weinan ; Cai, Chuang ; Chen, Weiping ; Liu, Ronghua ; Luo, Weihong ; Yin, Xinyou ; Lee, Xuhui - \ 2020
    Global Change Biology 26 (2020)3. - ISSN 1354-1013 - p. 1697 - 1713.
    acclimation - diffuse radiation - fertilization effect - global dimming - radiation use efficiency - rice - wheat - yield

    Global dimming, a decadal decrease in incident global radiation, is often accompanied with an increase in the diffuse radiation fraction, and, therefore, the impact of global dimming on crop production is hard to predict. A popular approach to quantify this impact is the statistical analysis of historical climate and crop data, or use of dynamic crop simulation modelling approach. Here, we show that statistical analysis of historical data did not provide plausible values for the effect of diffuse radiation versus direct radiation on rice or wheat yield. In contrast, our field experimental study of 3 years demonstrated a fertilization effect of increased diffuse radiation fraction, which partly offset yield losses caused by decreased global radiation, in both crops. The fertilization effect was not attributed to any improved canopy light interception but mainly to the increased radiation use efficiency (RUE). The increased RUE was explained not only by the saturating shape of photosynthetic light response curves but also by plant acclimation to dimming that gradually increased leaf nitrogen concentration. Crop harvest index slightly decreased under dimming, thereby discounting the fertilization effect on crop yields. These results challenge existing modelling paradigms, which assume that the fertilization effect on crop yields is mainly attributed to an improved light interception. Further studies on the physiological mechanism of plant acclimation are required to better quantify the global dimming impact on agroecosystem productivity under future climate change.

    The acclimation of leaf photosynthesis of wheat and rice to seasonal temperature changes in T-FACE environments
    Cai, Chuang ; Li, Gang ; Di, Lijun ; Ding, Yunjie ; Fu, Lin ; Guo, Xuanhe ; Struik, Paul C. ; Pan, Genxing ; Li, Haozheng ; Chen, Weiping ; Luo, Weihong ; Yin, Xinyou - \ 2020
    Global Change Biology 26 (2020)2. - ISSN 1354-1013 - p. 539 - 556.
    climate change - free-air CO enrichment - growth temperature - leaf nitrogen content - Oryza sativa L. - photosynthesis model - stomatal conductance - Triticum aestivum L.

    Crops show considerable capacity to adjust their photosynthetic characteristics to seasonal changes in temperature. However, how photosynthesis acclimates to changes in seasonal temperature under future climate conditions has not been revealed. We measured leaf photosynthesis (An) of wheat (Triticum aestivum L.) and rice (Oryza sativa L.) grown under four combinations of two levels of CO2 (ambient and enriched up to 500 µmol/mol) and two levels of canopy temperature (ambient and increased by 1.5–2.0°C) in temperature by free-air CO2 enrichment (T-FACE) systems. Parameters of a biochemical C3-photosynthesis model and of a stomatal conductance (gs) model were estimated for the four conditions and for several crop stages. Some biochemical parameters related to electron transport and most gs parameters showed acclimation to seasonal growth temperature in both crops. The acclimation response did not differ much between wheat and rice, nor among the four treatments of the T-FACE systems, when the difference in the seasonal growth temperature was accounted for. The relationships between biochemical parameters and leaf nitrogen content were consistent across leaf ranks, developmental stages, and treatment conditions. The acclimation had a strong impact on gs model parameters: when parameter values of a particular stage were used, the model failed to correctly estimate gs values of other stages. Further analysis using the coupled gs–biochemical photosynthesis model showed that ignoring the acclimation effect did not result in critical errors in estimating leaf photosynthesis under future climate, as long as parameter values were measured or derived from data obtained before flowering.

    Impacts of degrading permafrost on streamflow in the source area of Yellow River on the Qinghai-Tibet Plateau, China
    Ma, Qiang ; Jin, Hui Jun ; Bense, Victor F. ; Luo, Dong Liang ; Marchenko, Sergey S. ; Harris, Stuart A. ; Lan, Yong Chao - \ 2019
    Advances in Climate Change Research 10 (2019)4. - ISSN 1674-9278 - p. 225 - 239.
    Permafrost degradation - Source area of Yellow River (SAYR) - Streamflow - Streamflow patterns - Warming climate

    Many observations in and model simulations for northern basins have confirmed an increased streamflow from degrading permafrost, while the streamflow has declined in the source area of the Yellow River (SAYR, above the Tanag hydrological station) on the northeastern Qinghai-Tibet Plateau, West China. How and to what extent does the degrading permafrost change the flow in the SAYR? According to seasonal regimes of hydrological processes, the SAYR is divided into four sub-basins with varied permafrost extents to detect impacts of permafrost degradation on the Yellow River streamflow. Results show that permafrost degradation may have released appreciable meltwater for recharging groundwater. The potential release rate of ground-ice melt-water in the Sub-basin 1 (the headwater area of the Yellow River (HAYR), above the Huangheyan hydrological station) is the highest (5.6 mm per year), contributing to 14.4% of the annual Yellow River streamflow at Huangheyan. Seasonal/intra- and annual shifts of streamflow, a possible signal for the marked alteration of hydrological processes by permafrost degradation, is observed in the HAYR, but the shifts are minor in other sub-basins in the SAYR. Improved hydraulic connectivity is expected to occur during and after certain degrees of permafrost degradation. Direct impacts of permafrost degradation on the annual Yellow River streamflow in the SAYR at Tanag, i.e., from the meltwater of ground-ice, is estimated at 4.9% that of the annual Yellow River discharge at Tanag, yet with a high uncertainty, due to neglecting of the improved hydraulic connections from permafrost degradation and the flow generation conditions for the ground-ice meltwater. Enhanced evapotranspiration, substantial weakening of the Southwest China Autumn Rain, and anthropogenic disturbances may largely account for the declined streamflow in the SAYR.

    对农用地土壤环境质量类别划分的思考:以贵州马铃薯产区Cd风险管控为例
    Song, Jing ; Xu, Genyan ; Luo, Yongming ; Gao, Hui ; Tang, Wei - \ 2019
    Earth Science Frontiers 26 (2019)6. - ISSN 1005-2321 - p. 192 - 198.
    Bioavailable heavy metals - Criteria for safe utilization of soil - DUMIS - Soil-crop synchronized monitoring - Suitability assessment of soil environmental quality standard

    By compilation of data from field sampling, pot experiment and literature, we evaluated the suitability of the existing national standards (GB 15618-2018 and GB/T 36783-2018) for the classification of soil environmental quality in potato producing areas of Guizhou. The results showed that both soil Cd standards were overly stringent as, for example, these for potatoes grown in mining areas were more likely to exceed food standard. Here, we summarized the inadequacy of the existing sampling methods for soil-crop synchronized monitoring and proposed a sampling theory-based Decision Unit-Multi Increment Sampling method (DUMIS) for soil-crop synchronized monitoring and remediation verification. We proposed that the criteria for safe soil utilization should be derived on a site-specific basis using bioavailable fractions. In order to facilitate the evaluation of soil environmental quality and safety for the agricultural production regions of China, we suggested that further research is needed regarding the use of DUMIS in soil-crop synchronized monitoring and bioavailable fractions based criteria for safe utilization of mild to moderately contaminated soils.

    Biomarkers of Dietary Omega-6 Fatty Acids and Incident Cardiovascular Disease and Mortality: An Individual-Level Pooled Analysis of 30 Cohort Studies
    Marklund, Matti ; Wu, Jason H.Y. ; Imamura, Fumiaki ; Gobbo, Liana C. Del; Fretts, Amanda ; Goede, Janette De; Shi, Peilin ; Tintle, Nathan ; Wennberg, Maria ; Aslibekyan, Stella ; Chen, Tzu An ; Oliveira Otto, Marcia C. De; Hirakawa, Yoichiro ; Eriksen, Helle Højmark ; Kröger, Janine ; Laguzzi, Federica ; Lankinen, Maria ; Murphy, Rachel A. ; Prem, Kiesha ; Samieri, Cécilia ; Virtanen, Jyrki ; Wood, Alexis C. ; Wong, Kerry ; Yang, Wei Sin ; Zhou, Xia ; Baylin, Ana ; Boer, Jolanda M.A. ; Brouwer, Ingeborg A. ; Campos, Hannia ; Chaves, Paulo H.M. ; Chien, Kuo Liong ; Faire, Ulf De; Djoussé, Luc ; Eiriksdottir, Gudny ; El-Abbadi, Naglaa ; Forouhi, Nita G. ; Michael Gaziano, J. ; Geleijnse, Johanna M. ; Gigante, Bruna ; Giles, Graham ; Guallar, Eliseo ; Gudnason, Vilmundur ; Harris, Tamara ; Harris, William S. ; Helmer, Catherine ; Hellenius, Mai Lis ; Hodge, Allison ; Hu, Frank B. ; Jacques, Paul F. ; Jansson, Jan Håkan ; Kalsbeek, Anya ; Khaw, Kay Tee ; Koh, Woon Puay ; Laakso, Markku ; Leander, Karin ; Lin, Hung Ju ; Lind, Lars ; Luben, Robert ; Luo, Juhua ; Mcknight, Barbara ; Mursu, Jaakko ; Ninomiya, Toshiharu ; Overvad, Kim ; Psaty, Bruce M. ; Rimm, Eric ; Schulze, Matthias B. ; Siscovick, David ; Skjelbo Nielsen, Michael ; Smith, Albert V. ; Steffen, Brian T. ; Steffen, Lyn ; Sun, Qi ; Sundström, Johan ; Tsai, Michael Y. ; Tunstall-Pedoe, Hugh ; Uusitupa, Matti I.J. ; Dam, Rob M. van; Veenstra, Jenna ; Verschuren, Monique ; Wareham, Nick ; Willett, Walter ; Woodward, Mark ; Yuan, Jian Min ; Micha, Renata ; Lemaitre, Rozenn N. ; Mozaffarian, Dariush ; Risérus, Ulf - \ 2019
    Circulation 139 (2019)21. - ISSN 0009-7322 - p. 2422 - 2436.
    arachidonic acid - biomarkers - cardiovascular diseases - diet - epidemiology - linoleic acid - primary prevention

    Background: Global dietary recommendations for and cardiovascular effects of linoleic acid, the major dietary omega-6 fatty acid, and its major metabolite, arachidonic acid, remain controversial. To address this uncertainty and inform international recommendations, we evaluated how in vivo circulating and tissue levels of linoleic acid (LA) and arachidonic acid (AA) relate to incident cardiovascular disease (CVD) across multiple international studies. Methods: We performed harmonized, de novo, individual-level analyses in a global consortium of 30 prospective observational studies from 13 countries. Multivariable-adjusted associations of circulating and adipose tissue LA and AA biomarkers with incident total CVD and subtypes (coronary heart disease, ischemic stroke, cardiovascular mortality) were investigated according to a prespecified analytic plan. Levels of LA and AA, measured as the percentage of total fatty acids, were evaluated linearly according to their interquintile range (ie, the range between the midpoint of the first and fifth quintiles), and categorically by quintiles. Study-specific results were pooled using inverse-variance-weighted meta-analysis. Heterogeneity was explored by age, sex, race, diabetes mellitus, statin use, aspirin use, omega-3 levels, and fatty acid desaturase 1 genotype (when available). Results: In 30 prospective studies with medians of follow-up ranging 2.5 to 31.9 years, 15 198 incident cardiovascular events occurred among 68 659 participants. Higher levels of LA were significantly associated with lower risks of total CVD, cardiovascular mortality, and ischemic stroke, with hazard ratios per interquintile range of 0.93 (95% CI, 0.88-0.99), 0.78 (0.70-0.85), and 0.88 (0.79-0.98), respectively, and nonsignificantly with lower coronary heart disease risk (0.94; 0.88-1.00). Relationships were similar for LA evaluated across quintiles. AA levels were not associated with higher risk of cardiovascular outcomes; in a comparison of extreme quintiles, higher levels were associated with lower risk of total CVD (0.92; 0.86-0.99). No consistent heterogeneity by population subgroups was identified in the observed relationships. Conclusions: In pooled global analyses, higher in vivo circulating and tissue levels of LA and possibly AA were associated with lower risk of major cardiovascular events. These results support a favorable role for LA in CVD prevention.

    Effect of early life and current environmental enrichment and personality on attention bias in pigs
    Luo, Lu ; Reimert, I. ; Haas, E.N. de; Kemp, B. ; Bolhuis, J.E. - \ 2019
    In: Proceedings of the 53rd Congress of the International Society for Applied Ethology (ISAE). - Wageningen, The Netherlands : Wageningen Academic Publishers - ISBN 9789086863389 - p. 128 - 128.
    Animals may show increased attention towards threatening stimuli when they are in a negativeaffective state, i.e. attention bias. A barren, stimulus-poor housing environment can inducestress and potentially a negative mood in pigs. Apart from current housing conditions, however,also the early life environment and personality characteristics might influence affective state.In this study, we aimed to investigate the effects of early life and current housing conditionsand personality (coping style) on attention bias in pigs. Pigs (n=128, 32 pens) housed inbarren or enriched housing in early life (B1 vs E1), experienced either a switch in housingconditions at 7 wks of age or not (creating B1B2, B1E2, E1E2 and E1B2 treatments). Theywere classified using a backtest as ‘high resister’ (HR, proactive coping style) or ‘low resister’(LR, reactive coping style) at 2 wks. Pigs were subjected to a 3-min attention bias test at 11wks of age. Half of the pigs were exposed to a 10-sec potential threat (T) and the other halfnot (C) in a test room with food in the centre. Attention towards the (location of the) threat,vigilance, eating and vocalisations were recorded. Firstly, behaviours of T and C pigs over thetest were compared. Secondly, for T pigs, effects of early life and current housing, coping styleand their interactions on behaviour during and for 150 sec after the threat were tested. Mixedmodels with random pen effects were used, except for squealing for which a Fisher’s exact testwas used. T pigs spent more time on vigilance behaviour (T: 13.6±1.4, C: 6.8±1.0%, P<0.001),less time on eating (T: 15.0±1.8, C: 27.8±2.4%, P<0.001), were more likely to squeal (T: 22%C: 6% of pigs, P<0.05) than C pigs, and paid more attention to the location of the threat (T:7.1±0.6, C: 0.5±0.1% of time, P<0.001) throughout the 3-min test, indicating that pigs didrespond to the threat. During presence of the threat, HR pigs showed more vigilance (P<0.05),particularly in E2 housing (E2-HR: 39.9±6.6, E2-LR: 6.7±2.9, B2-HR: 19.4±5.9, and B2-LR:12.1±4.4%, interaction P<0.05). E1-HR pigs (55.4±6.5%) tended to pay more attention to thethreat than E1-LR pigs (30.3±5.9%), with levels of B1-HR (46.4±6.8%) and B1-LR (48.3±7.6%)in between (interaction P<0.10). After presence of the threat, no effects of housing or copingstyle on vigilance, attention to location of the threat or eating were found. E2 pigs grunted moreoften than B2 pigs (9.6±1.7 vs 3.6±0.9 per min, P<0.01). E2 pigs were also more likely to squealthan B2 pigs (P<0.05), particularly the HR pigs (E2-HR: 50%, B2-HR: 0%, E2-LR: 21%, B2-LR:17%, interaction P<0.10). In conclusion, housing affected vigilance in a personality-dependentmanner during a short period of exposure to a potential threat. We found no strong effect ofearly life or current housing on attention bias after the threat, but current housing conditionsand personality did affect vocalisations.
    Effect of early life and current environmental enrichment and personality on attention bias in pigs
    Luo, Lu - \ 2019
    Effects of early and later life environmental enrichment and personality on attention bias in pigs (Sus scrofa domesticus)
    Luo, Lu ; Reimert, Inonge ; Haas, Elske N. de; Kemp, Bas ; Bolhuis, J.E. - \ 2019
    Animal Cognition 22 (2019)6. - ISSN 1435-9448 - p. 959 - 972.
    Affective states - Attention bias - Coping style - Early life - Environmental enrichment - Pigs

    We investigated effects of early and later life housing on attention bias, as an indicator of affective state, in pigs differing in coping style [reactive (LR) vs. proactive (HR)]. Pigs (n = 128) in barren or enriched housing from birth (B1 vs. E1) that experienced either a switch in housing at 7 weeks of age or not (creating B1B2, B1E2, E1E2, and E1B2 treatments), were studied in a 180-s attention bias test at 11 weeks. Pigs exposed to a 10-s-auditory-and-sudden-motion threat in the test arena paid more attention to the location of the threat, were more vigilant, showed less eating, more walking and were more likely to utter high-pitched vocalisations than non-threat pigs. During threat presence, HR pigs from post-switch enriched housing (E2-HR, i.e., B1E2 + E1E2) showed more vigilance but less exploration than others. After threat removal, no effects were found on time spent paying attention to the threat, vigilance, and eating, but E2-HR pigs paid attention to the threat more frequently, were more likely to utter high-pitched vocalisations and walked more compared to (part of) other groups, suggesting the most negative affective state in these animals. E2 pigs grunted more than B2 pigs. Thus, current housing, but not early life housing, affected behaviour in a personality-dependent manner in this attention bias test. Housing effects were opposite to expectation, possibly due to the short-term effect of the relative contrast between the home pens of the pigs and the test room. This potentially overruled putative long-term effects of environmental conditions on attention bias.

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