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41.
Increasing reactive nitrogen (N) input has been recognized as one of the important factors influencing climate system through affecting the uptake and emission of greenhouse gases (GHG). However, the magnitude and spatiotemporal variations of N‐induced GHG fluxes at regional and global scales remain far from certain. Here we selected China as an example, and used a coupled biogeochemical model in conjunction with spatially explicit data sets (including climate, atmospheric CO2, O3, N deposition, land use, and land cover changes, and N fertilizer application) to simulate the concurrent impacts of increasing atmospheric and fertilized N inputs on balance of three major GHGs (CO2, CH4, and N2O). Our simulations showed that these two N enrichment sources in China decreased global warming potential (GWP) through stimulating CO2 sink and suppressing CH4 emission. However, direct N2O emission was estimated to offset 39% of N‐induced carbon (C) benefit, with a net GWP of three GHGs averaging ?376.3 ± 146.4 Tg CO2 eq yr?1 (the standard deviation is interannual variability of GWP) during 2000–2008. The chemical N fertilizer uses were estimated to increase GWP by 45.6 ± 34.3 Tg CO2 eq yr?1 in the same period, and C sink was offset by 136%. The largest C sink offset ratio due to increasing N input was found in Southeast and Central mainland of China, where rapid industrial development and intensively managed crop system are located. Although exposed to the rapidly increasing N deposition, most of the natural vegetation covers were still showing decreasing GWP. However, due to extensive overuse of N fertilizer, China's cropland was found to show the least negative GWP, or even positive GWP in recent decade. From both scientific and policy perspectives, it is essential to incorporate multiple GHGs into a coupled biogeochemical framework for fully assessing N impacts on climate changes. 相似文献
42.
微阵列技术是生物技术变革的核心,允许研究者同时监测成千上万个基的表达水平,已广泛应用医学研究.如何挖掘海量基表达信息中的有用信息并进行生物学专业解释,是基表达谱数据分析领所面临的一个重要挑战.生物信号通路研究已成为基芯片中不同表型差异表达研究的主要方法,其是以整个信号通路作为一个整体作为研究对象,此得出的研究结果更加科学和准确.在本文中我们简要描述了近10年来信号通路基集富集分析方法的发展情况,将其分为三个阶段,对每个阶段方法的基础和特点做了一些简单的总结和阐述. 相似文献
43.
CO2加富对盐胁迫下黄瓜幼苗叶片光合特性及活性氧代谢的影响 总被引:1,自引:0,他引:1
以‘津优35号’黄瓜(Cucumis sativus L.)水培苗为试材,采用裂区设计,主区因素为CO_2浓度处理,设大气CO_2浓度(Symbol{B@400μmol/mol)和CO_2加富[(800±40)μmol/mol]2个CO_2浓度水平,裂区因素为盐胁迫处理,用NaCl模拟盐胁迫,设对照(0 mmol/L NaCl)、盐胁迫(80 mmol/L NaCl)2个盐分水平,研究了CO_2加富对盐胁迫下黄瓜幼苗生长、光合特性及活性氧代谢的影响。结果表明:盐胁迫显著抑制黄瓜幼苗的生长,并降低了叶绿素含量、ETR、Φ_(PSII)、核酮糖-1,5-二磷酸羧化酶(RuBPCase)活性及净光合速率;盐胁迫增加了丙二醛及活性氧的累积,与此同时也提高了脯氨酸含量及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性,但降低了过氧化物酶(POD)活性。CO_2加富显著提高了盐胁迫下黄瓜幼苗的株高、茎粗、叶面积及地上部鲜重,降低了叶绿素a、叶绿素b、类胡萝卜素及叶绿素(a+b)含量,但显著提高了净光合速率和RuBPCase活性,同时降低了气孔导度及蒸腾速率,并且使其具有较高的表观电子传递速率及PSII实际光化学效率;CO_2加富显著提高了盐胁迫下黄瓜幼苗叶片脯氨酸含量及SOD、POD、CAT活性,丙二醛、过氧化氢含量和超氧阴离子产生速率显著降低。综上所述,CO_2加富可通过提高幼苗叶片净光合速率、脯氨酸含量及抗氧化酶活性,降低蒸腾速率、减少丙二醛含量及活性氧的积累,从而缓解盐胁迫对黄瓜植株造成的伤害。 相似文献
44.
镉胁迫对紫花苜蓿幼苗生理特性和镉富集的影响 总被引:1,自引:0,他引:1
以"甘农三号"紫花苜蓿幼苗为材料,在水培条件下,探究了在10 d内不同浓度(0~2.0 mmol·L-1)镉(Cd)胁迫对其根长、茎长、生物量、叶绿素和丙二醛(MDA)含量、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性、Cd富集及其亚细胞分布的影响。结果表明:低浓度(0.125 mmol·L-1) Cd能促进幼苗根和茎的生长,增加叶片叶绿素含量,较高浓度(0.5~2.0 mmol·L-1) Cd显著抑制幼苗根和茎的生长,叶绿素及生物量显著降低; Cd胁迫使MDA含量显著增加,而SOD和POD活性显著增强,其中Cd胁迫浓度为0.5mmol·L-1时,SOD和POD活性达到最大值,这可能是植物对环境胁迫的一种应激保护反应; Cd在各亚细胞组分中的含量依次为细胞壁>细胞质>线粒体>叶绿体,且均随Cd胁迫浓度的升高而增加。当Cd胁迫浓度为0.125 mmol·L-1时,水培10 d的紫花苜蓿幼苗单株地上部对Cd的净化率最高可达0.214%,而整盆植株在单位体积内对Cd的净化率最高可达15.5%;当Cd胁迫浓度为2.0 mmol·L-1时,紫花苜蓿幼苗地上部Cd含量达89.36μg·g-1。这些结果表明紫花苜蓿对Cd具有很强的富集能力,虽未达到Cd超富集植物的临界标准,但从植株生物量、耐Cd能力、富集Cd量及对Cd的净化率等方面综合考虑,紫花苜蓿在Cd污染土壤的植物修复中具备良好的应用价值。 相似文献
45.
ngela M. Ribeiro Lara Puetz Nicholas B. Pattinson Love Daln Yuan Deng Guojie Zhang Rute R. da Fonseca Ben Smit M. Thomas P. Gilbert 《Molecular ecology》2019,28(16):3709-3721
Arid environments provide ideal ground for investigating the mechanisms of adaptive evolution. High temperatures and low water availability are relentless stressors for many endotherms, including birds; yet birds persist in deserts. While physiological adaptation probably involves metabolic phenotypes, the underlying mechanisms (plasticity, genetics) are largely uncharacterized. To explore this, we took an intraspecific approach that focused on a species that is resident over a mesic to arid gradient, the Karoo scrub‐robin (Cercotrichas coryphaeus). Specifically, we integrated environmental (climatic and primary productivity), physiological (metabolic rates: a measure of energy expenditure), genotypic (genetic variation underlying the machinery of energy production) and microbiome (involved in processing food from where energy is retrieved) data, to infer the mechanism of physiological adaptation. We that found the variation in energetic physiology phenotypes and gut microbiome composition are associated with environmental features as well as with variation in genes underlying energy metabolic pathways. Specifically, we identified a small list of candidate adaptive genes, some of them with known ties to relevant physiology phenotypes. Together our results suggest that selective pressures on energetic physiology mediated by genes related to energy homeostasis and possibly microbiota composition may facilitate adaptation to local conditions and provide an explanation to the high avian intraspecific divergence observed in harsh environments. 相似文献
46.
Taylor Eagan 《Journal of applied animal welfare science : JAAWS》2019,22(1):69-77
Studies on environmental enrichment for reptiles are lacking in the scientific literature. Although the literature reflects a limited take on reptile enrichment in the zoological community, it may not be the case in reality as enrichment is generally considered an important aspect of the care of nonhuman animals in captivity. This project investigated the current state of reptile enrichment as it is being used in zoos. Although respondents were disproportionately accredited by the Association of Zoos and Aquariums, the results showed many forms of enrichment being used for reptiles in zoos and happening at much greater levels than what has been suggested in the scientific literature. There were significant differences between a) reptile groups for each form of enrichment, and b) enrichment forms within each reptile group, except with the use of natural enrichment devices and structural/habitat design, which did not differ across all reptile groups. Enrichment goals, assessment methods, and sources of information for reptile enrichment used by zoos suggest the need for more scientific publications for facilities to make evidence-based decisions to improve the welfare of reptiles in captivity. 相似文献
47.
BRIONY C. Strachan HUI XIA ESZTER VÖRÖS SEAN C. GIFFORD SERGEY S. SHEVKOPLYAS 《Cytotherapy》2019,21(2):234-245
Background
The isolation of lymphocytes – and removal of platelets (PLTs) and red blood cells (RBCs) – from an initial blood sample prior to culture is a key enabling step for effective manufacture of cellular therapies. Unfortunately, currently available methods suffer from various drawbacks, including low cell recovery, need for complex equipment, potential loss of sterility and/or high materials/labor cost.Methods
A newly developed system for selectively concentrating leukocytes within precisely designed, but readily fabricated, microchannels was compared with conventional density gradient centrifugation with respect to: (i) ability to recover lymphocytes while removing PLTs/RBCs and (ii) growth rate and overall cell yield once expanded in culture.Results
In the optimal embodiment of the new microfluidic approach, recoveries of CD3+, CD19+ and CD56+ cells (85%, 89% and 97%, respectively) were significantly higher than for paired samples processed via gradient-based separation (51%, 53% and 40%). Although the removal of residual PLTs and RBCs was lower using the new approach, its enriched T-cell fraction nevertheless grew at a significantly higher rate than the gradient-isolated cells, with approximately twice the cumulative cell yield observed after 7 days of culture.Discussion
The standardization of each step of cellular therapy manufacturing would enable an accelerated translation of research breakthroughs into widely available clinical treatments. The high-throughput approach described in this study – requiring no ancillary pumping mechanism nor expensive disposables to operate – may be a viable candidate to standardize and streamline the initial isolation of lymphocytes for culture while also potentially shortening the time required for their expansion into a therapeutic dose. 相似文献48.
Zhongyin Yang Chen Li Chao Yan Jianfang Li Min Yan Bingya Liu Zhenggang Zhu Yingli Wu Qinlong Gu 《生物化学与生物物理学报:疾病的分子基础》2019,1865(1):181-192
The kinesin family member 14 (KIF14) is a potential oncogene and is involved in the metastasis of various cancers. Nevertheless, its function in gastric cancer (GC) remains poorly defined. The expression of KIF14 was examined in GC cell lines and a clinical cohort of GC specimens by qPCR, western blotting and immunohistochemistry (IHC) staining. The relationship between KIF14 expression and the clinicopathological features was analyzed. The effect of KIF14 on cell proliferation, colony formation, invasion and migration were investigated in vitro and in vivo. The expression of KIF14 was significantly increased in the GC tissues and cell lines. High KIF14 expression was associated with tumor stage, tumor-node-metastasis (TNM) stage and metastasis. KIF14 was an independent prognostic factor for the overall survival of GC, and a higher expression of KIF14 predicted a poorer survival. KIF14 silencing resulted in attenuated proliferation, invasion and migration in human gastric cancer cells, whereas KIF14 ectopic expression facilitated these biological abilities. Notably, the depressed expression of KIF14 inhibited Akt phosphorylation, while overexpressed KIF14 augmented Akt phosphorylation. Additionally, there was a significant correlation between the expression of KIF14 and p?Akt in GC tissues. Importantly, the proliferation, invasion and migration of the GC cells, which was promoted by KIF14 overexpression, was abolished by the Akt inhibitor MK-2206, while Akt overexpression greatly rescued the effects induced by KIF14 knockdown. Our findings are the first to demonstrate that KIF14 is overexpressed in GC, is correlated with poor prognosis and plays a crucial role in the progression and metastasis of GC. 相似文献
49.
Bolun Cheng Xiao Liang Yan Wen Ping Li Lu Zhang Mei Ma Shiqiang Cheng Yanan Du Li Liu Miao Ding Yan Zhao Feng Zhang 《Journal of cellular biochemistry》2019,120(9):14831-14837
50.
Shirin Kouhpayeh Zahra Hejazi Maryam Boshtam Mina Mirian Ilnaz Rahimmanesh Leila Darzi Abbas Rezaei Laleh Shariati Hossein Khanahmad 《Journal of cellular biochemistry》2019,120(9):16264-16272
One of the most important molecules for multiple sclerosis pathogenesis is α4 integrin, which is responsible for autoreactive leukocytes migration into the brain. The monoclonal antibody, natalizumab, was introduced to market for blocking the extravasation of autoreactive leukocytes via inhibition of α4 integrin. However, the disadvantages of antibodies provided a suitable background for other agents to be replaced with antibodies. Considering the profound advantages of aptamers over antibodies, aptamer isolation against α4 integrin was intended in the current study. The α4 integrin-specific aptamers were selected using cell-systematic evolution of ligands by exponential enrichment (SELEX) method with human embryonic kidney (HEK)-293T overexpressing α4 integrin and HEK-293T as target and control cells, respectively. Evaluation of selected aptamer was performed through flow cytometric analysis. The selected clones were then sequenced and analyzed for any possible secondary structure and affinity. The results of this study led to isolation of 13 different single-stranded DNA clones in 11 rounds of selection which were categorized to three clusters based on common structural motifs and the equilibrium dissociation constant (K d) of the most stable structure was calculated. The evaluation of SELEX progress showed growth in aptamer affinity with increasing of the number of cycles. Taken together, the findings of this study demonstrated the isolation of α4-specific single-stranded DNA aptamers with suitable affinity for ligand, which can further be replaced with natalizumab. 相似文献